Intel Core Processors
Intel Core i3, Core i5, and Core i7 CPUs have been around for over a year now, but
some buyers still get stumped whenever they attempt to build their own systems and
are forced to choose among the three. With the more recent Sandy Bridge
architecture now on store shelves, we expect the latest wave of buyers to ask the
same kind of questions.
Core i3, Core i5, Core i7 — the
difference in a nutshell
If you want a plain and simple answer, then generally speaking, Core i7s are better
than Core i5s, which are in turn better than Core i3s. Nope, Core i7 does not have
seven cores nor does Core i3 have three cores. The numbers are simply indicative
of their relative processing powers.
Their relative levels of processing power are also signified by their Intel Processor
Star Ratings, which are based on a collection of criteria involving their number of
cores, clockspeed (in GHz), size of cache, as well as some new Intel technologies
like Turbo Boost and Hyper-Threading.
Core i3s are rated with three stars, i5s have four stars, and i7s have five. If you’re
wondering why the ratings start with three, well they actually don’t. The entry-level
Intel CPUs — Celeron and Pentium — get one and two stars respectively.
Number of cores
The more cores there are, the more tasks (known as threads) can be served at the
same time. The lowest number of cores can be found in Core i3 CPUs, i.e., which
have only two cores. Currently, all Core i3s are dual-core processors.
Currently all Core i5 processors, except for the i5-661, are quad cores in Australia.
The Core i5-661 is only a dual-core processor with a clockspeed of 3.33 GHz.
Remember that all Core i3s are also dual cores. Furthermore, the i3-560 is also
3.33GHz, yet a lot cheaper. Sounds like it might be a better buy than the i5. What
gives?
At this point, I’d like to grab the opportunity to illustrate how a number of factors
affect the overall processing power of a CPU and determine whether it should be
considered an i3, an i5, or an i7.
Even if the i5-661 normally runs at the same clockspeed as Core i3-560, and even if
they all have the same number of cores, the i5-661 benefits from a technology
known as Turbo Boost.
Intel Turbo Boost
The Intel Turbo Boost Technology allows a processor to dynamically increase its
clockspeed whenever the need arises. The maximum amount that Turbo Boost can
raise clockspeed at any given time is dependent on the number of active cores, the
estimated current consumption, the estimated power consumption, and the
processor temperature.
For the Core i5-661, its maximum allowable processor frequency is 3.6 GHz.
Because none of the Core i3 CPUs have Turbo Boost, the i5-661 can outrun them
when it needs to. Because all Core i5 processors are equipped with the latest
version of this technology — Turbo Boost 2.0 — all of them can outrun any Core i3.
Cache size
Whenever the CPU finds that it keeps on using the same data over and over, it
stores that data in its cache. Cache is just like RAM, only faster — because it’s built
into the CPU itself. Both RAM and cache serve as holding areas for frequently used
data. Without them, the CPU would have to keep on reading from the hard disk
drive, which would take a lot more time.
Basically, RAM minimises interaction with the hard disk, while cache minimises
interaction with the RAM. Obviously, with a larger cache, more data can be
accessed quickly. All Core i3 processors have 3MB of cache. All Core i5s, except
again for the 661 (only 4MB), have 6MB of cache. Finally, all Core i7 CPUs have
8MB of cache. This is clearly one reason why an i7 outperforms an i5 — and why an
i5 outperforms an i3.
Hyper-Threading
Strictly speaking, only one thread can be served by one core at a time. So if a CPU
is a dual core, then supposedly only two threads can be served simultaneously.
However, Intel has introduced a technology called Hyper-Threading. This enables a
single core to serve multiple threads.
For instance, a Core i3, which is only a dual core, can actually serve two threads per
core. In other words, a total of four threads can run simultaneously. Thus, even if
Core i5 processors are quad cores, since they don’t support Hyper-Threading
(again, except the i5-661) the number of threads they can serve at the same time is
just about equal to those of their Core i3 counterparts.
This is one of the many reasons why Core i7 processors are the creme de la creme.
Not only are they quad cores, they also support Hyper-Threading. Thus, a total of
eight threads can run on them at the same time. Combine that with 8MB of cache
and Intel Turbo Boost Technology, which all of them have, and you’ll see what sets
the Core i7 apart from its siblings.
The upshot is that if you do a lot of things at the same time on your PC, then it might
be worth forking out a bit more for an i5 or i7. However, if you use your PC to check
emails, do some banking, read the news, and download a bit of music, you might be
equally served by the cheaper i3.
At DCA Computers, we regularly hear across the sales counter, “I don’t mind paying
for a computer that will last, which CPU should I buy?” The sales tech invariably
responds “Well that depends on what you use your computer for.” If it’s the scenario
described above, we pretty much tell our customers to save their money and buy an
i3 or AMD dual core.
Another factor in this deliberation is that more and more programs are being
released with multithread capability. That is they can use more than one CPU thread
to execute a single command. So things happen more quickly. Some photo editors
and video editing programs are multi-threaded, for example. However, the Internet
browser you use to access Netbank or your email client is not, and is unlikely to be
in the foreseeable future.
Desktop CPUs
Frequency
Turbo
Boost
Cores Hyperthreading
Smart
Cache
TDW
Graphics
Core
i7
2.0-3.5GHz
4
8MB
3584W
Intel HD
4600
Core
i5
3.0-3.4GHz
4
4-6MB
3584W
Intel HD
4600
Core
i3
2.4-3.6GHz
2
3-4MB
3554W
Varies
Overall, the chart above can be summarized with the following:
1. The CPU frequency and thermal output (TDW) is largely not determined
by the Core i_ name
2. Core i5 and i7 both have Turbo Boost while the i3 does not
3. Core i5 and i7 CPUs have 4 cores, while i3 CPUs only have 2
4. Core i5 CPUs lack Hyperthreading
5. Core i7 CPUs have more Smart Cache than i5 CPUs, which in turn have
more cache than i3 CPUs
6. Core i5 and i7 CPUs have the same graphics, although the speed of that
graphics will depend on the individual CPU. Core i3 CPUs have variable
graphics depending on the price-point of the CPU.
So while i7 CPUs do have overall better specifications than i5 CPUs, there is
actually quite a bit of overlap between the two except that i5 CPUs do not
support Hyperthreading. Especially in terms of frequency and thermal output,
the two lines really are not very different. For i3 CPUs, the main difference is
that they only have two cores, a smaller cache, do not support Turbo Boost and
have overall lower thermal output than i5 and i7 CPUs.
Mobile CPUs
Frequency
Turbo
Boost
Cores Hyperthreading
Smart
Cache
TDW
Graphics
Core i7
2.7-3.0
GHz
4
6-8MB
4757W
Intel HD
4600
Core i5
Unreleased
1.5-2.8
GHz
2
3MB
1757W
Intel HD
4600
Core i3
Unreleased
1.4-2.6
GHz
2
3MB
1345W
Intel HD
4600
Currently, there are no Haswell Core i3 or i5 mobile CPUs available for
consumers. The values in the chart above are our prediction based on previous
generations.
Overall, the chart above can be summarized with the following:
1. There is a lot of overlap in CPU frequency and thermal output (TDW)
between i3, i5 and i7 CPUs. Core i7 CPUs will have a slightly higher topend frequency and wattage, while i3/i5 CPUs have lower bottom-end
frequency and wattage.
2. All Haswell mobile CPUs released so far have both Turbo
Boost and Hyperthreading (although i3 is likey to not support Turbo
Boost)
3. Core i7 CPUs have 4 cores, while i5 and i3 CPUs (should) only have 2
4. Core i7 CPUs have more Smart Cache than i5 and i3 CPUs
5. All CPUs have the same graphics core (although i3 and i5 is unconfirmed),
although the speed of that graphics will depend on the individual CPU
In this case, the main advantage of the Core i7 CPUs is that they have 4 cores,
but at the same time they also have an overall higher thermal output. Core i5
and i3 CPUs are actually very similar to each other except that the i3 CPUs are
likely to not support Turbo Boost and have slightly lower frequency and power
draw than the i5 CPUs.
Question Related to i3,i5,i7 processor
What the difference between Intel Cores: Number of cores
What the difference between Intel Cores: Intel Turbo Boost
What the difference between Intel Cores: Cache size
What the difference between Intel Cores: Hyper-Threading
Difference between Core i3, Core i5 and Core i7
Intel will stop selling Core 2 Duo and Core 2 Quad in 2010. Core is the new range of Intel
processors.
Core i3:
* Entry level processor.
* 2-4 Cores
* 4 Threads
* Hyper-Threading (efficient use of processor resources)
* 3-4 MB Catche
* 32 nm Silicon (less heat and energy)
Core i5:
* Mid range processor.
* 2-4 Cores
* 4 Threads
* Turbo Mode (turn off core if not used)
* Hyper-Threading (efficient use of processor resources)
* 3-8 MB Catche
* 32-45 nm Silicon (less heat and energy)
Core i7:
* High end processor.
* 4 Cores
* 8 Threads
* Turbo Mode (turn off core if not used)
* Hyper-Threading (efficient use of processor resources)
* 4-8 MB Catche
* 32-45 nm Silicon (less heat and energy)
List of Core_i3 families
Core i3
Author: gshv
Desktop Core i3 family spans three generations of processors, Westemere-based Core i3-5xx
series, Sandy Bridge-based i3-2xxx, and finally i3-3xxx, built on Ivy Bridge architecture.
Different generations have somewhat different feature sets. Most notably, Westmere chips
have 4 MB L3 cache and fit into socket 1156. The second Core i3 generation doubles DMI
interface bandwidth, adds AVX instructions, and has better graphics. Additionally, the
processors have lower TDP and fit into socket 1155. The size of L3 cache of these chips was
reduced to 3 MB. The third i3 generation has all of the features of its predecessor, and it
further improves on-chip graphics and TDP. Regardless of their underlying microarchitecture,
all Core i3 CPUs have 2 cores, and support Hyper-Threading technology, which allows them to
run 4 threads at once. The i3 desktop microprocessors have very decent performance, which
is close to or exceeds performance of the fastest Core 2 Duo parts. Core i3s are not as fast as
Core i5 and i7 CPUs, but they are priced much cheaper, and, consequently, have better price /
performance ratio.
Picture of: Intel Core i3-530 - CM80616003180AG / BX80616I3530 / BXC80616I3530
Core i3 Mobile
Author: gshv
Mobile Core i3s run at considerably lower clock speeds than desktop CPUs, but they have
much lower power dissipation - 35 Watt for mainstream parts, or 17 Watt for Ultra Low
Voltage parts. Similar to the Core i3 desktop family, mobile i3 microprocessors span 3
successive microarchitecture generations, with each new generation adding more and more
features. Core i3-3xx "Westmere" processors from the first generation had 3 MB L3 cache,
SIMD support up to SSE4, and they either required socket G1 or were soldered on the
motherboard. Core i3-2xxx "Sandy Bridge" CPUs introduced AVX instructions, had better
integrated graphics and faster DMI interface. These microprocessors were either soldered on
the board, or needed socket G2, which was not compatible with socket G1. Core i3-3xxx "Ivy
Bridge" parts feature improved CPU and graphics performance. These processors come with
the same features and use the same socket as the second Core i3 generation, however the Ivy
Bridge chips cannot be used to upgrade older 6-series motherboards. In the second half 2013,
Intel will introduce Haswell-based Core i3 processors, that will have even better performance,
although they won't be compatible with socket G1 and socket G2 laptops.
Intel Core i3-3220 Processor is a new low cost i3 sires processor from Intel. The Intel Core i33220 Processor integrated with 2 cores and 3MB Internal cache. The processor has 4 threads
which will virtually work like 4 cores. This 64bit processor is coming with Intel HD Graphics 2500.
Below we given the advanced technologies added in this processor.
1.
Intel Hyper-Threading Technology
2.
Intel 64
3.
Intel Virtualization Technology (VT-x)
4.
Intel My WiFi Technology
5.
Intel Anti-Theft Technology
6.
Idle States
7.
Enhanced Intel SpeedStep Technology
8.
Thermal Monitoring Technologies
9.
Intel VT-x with Extended Page Tables (EPT)
10.
Execute Disable Bit
Intel Core i3-3220 Processor Features

No of Cores:2

3.3 GHz Clock speed

3 MB Intel Smart Cache

64-bit Instruction Set

22 nm core technology

55 W Max Thermal Design Power (TDP)

Supported memory size: 32GB
Intel Core i3-3220 Processor Specifications
Processor
Intel i3-3220
Supported Socket
FCLGA1155
No of Cores
2
Number of Threads
4
Clock Speed
3.3 GHz
Intel Smart Cache
3 MB
DMI
5 GT/s
Instruction Set
64-bit
Instruction Set Extensions
SSE4.1/4.2, AVX
Core technology (Lithography)
22 nm
Max Thermal Design Power (TDP)
55 W
VID Voltage Range
-
Supported memory size and type
32 GB DDR3-1333/1600
Number of Memory Channels
2
Max Memory Bandwidth
25.6 GB/s
Processor Graphics
Intel HD Graphics 2500
Number of Displays Supported
3
Intel Core i5 Processor - An
Overview of Key Features and
Benefits
When it comes to excellence in processor performance, Intel continues to pull all the stops with its newest
entries into the market. Launched in early September, 2009, the Intel Core i5 processor is one of Intel's
recent innovations, which offers smart performance with a speed boost. This processor delivers solid
performance for day-to-day applications, not to mention its ability to increase speed as required for the more
demanding tasks. And already, it's being touted as the mainstream version of Intel Core i7.
Mobility
Intel Core i5 processor will power an ultra thin laptop to boost not only your performance, but your style as
well. You can now indulge in a much faster, smarter and thinner laptop than before, in an ultra-sleek design
and with enhanced battery life. A thinner laptop weighs less and is more portable, therefore allowing for
greater mobility.
Performance
Intel Core i5 Turbo Boost Technology allows for automatic speeding up of the processor when the PC
requires extra performance, thus giving you smart performance with a speed boost. This feature is however
only available in select models of the Intel Core i5 processor-based systems.
Intel Hyper-Threading Technology features 4-way multi-task processing which enables each core of the
processor to handle 2 tasks simultaneously, thus delivering the performance required for smart multitasking.
No matter how many applications you are working with at the same time, you and your PC will not be slowed
down at all.
Intel HD Graphics technology is included to provide excellent visual performance for rich color, sharp
imaging, as well as life-like video and audio. You can now enjoy your movies and internet videos in highdefinition, get full Microsoft Windows 7 support, as well as play popular game titles. You can do all this
without the need for an extra add-in video card as this is all built-in.
Laptops powered by Intel Core i5 processor and featuring 4g WiMAX wireless technology can deliver great
smart performance from internet speed which is four times faster than 3G.
Compatibility
Intel Core i5 processors are used to power ultra thin laptops such as the Sony VAIO Series, HP dv4, Dell
Inspiron 15R, Toshiba Satellite L500, HP Pavilion dv4i Series, CyberPower Xplorer X5, Sager NP7652,
ASUS N61JV, CyberPower Xplorer X5 and the Lenovo ThinkPad T Series.
Security
Intel Core i5 is optimized for a number of security-related technologies including MacAfee security, WinZip
file compression, the Bit Locker in 64-bit Windows 7, as well as PGP security. This will come as a relief for
laptop owners, seeing as an estimated 12,000 laptops get stolen each week from airports alone.
Some more Features
• Intel Core i5-700 and i5-600 processor series with Intel Turbo Boost Technology;
• 4 processing threads;
• Up to 8 MB of Intel Smart Cache;
• Intel HD Graphics on Intel Core i5-600 processor series; and,
• 2 channels of DDR3 1333 MHz memory.
Intel has long been recognized as the leading name in cutting-edge performance processors, and the Intel
Core i5 very well lives up to this reputation.
Processor NumberOrdering CodeCache, Clock
SpeedPowerMemoryProduct TechnologiesIntel® Pentium® processor
G6950CM80616004593AE3 MB, 2.8 GHz73 WDDR3-1066Enhanced
Intel SpeedStep® Technology, IA-64, Execute Disable Bit
Intel® Core™ i7-860 processorBV80605001908AK8 MB, 2.8 GHz95
WDDR3-1066/1333Enhanced Intel SpeedStep Technology, Intel®
Hyper-Threading Technology (Intel® HT Technology), IA-64,
Intel® Trusted Execution Technology (Intel® TXT), Intel® vPro™
technology, Intel® Virtualization Technology (Intel® VT) for
Directed I/O (Intel® VT-d), Execute Disable Bit
Intel® Core™ i5-750 processorBV80605001911AP8 MB, 2.66 GHz95
WDDR3-1066/1333Enhanced Intel SpeedStep Technology, IA-64,
Execute Disable Bit
Intel® Core™ i5-660 processorCM80616003177AC4 MB, 3.33 GHz73
WDDR3-1066/1333Intel® AES New Instructions (Intel® AES-NI),
Enhanced Intel SpeedStep Technology, Intel HT Technology, IA64, Intel TXT, Intel vPro technology, Intel VT-d, Execute Disable
Bit
Intel® Core™ i3-540 processorCM80616003060AE4 MB, 3.06 GHz73
WDDR3-1066/1333Enhanced Intel SpeedStep Technology, Intel
HT Technology, IA-64, Execute Disable Bit
Chipsets
ProductOrdering CodePackagePowerFeatures
Intel® Q57 PCHBD82Q57FCBGA9515.1 WIntel® Active Management
Technology, six eSATA ports, 14 USB ports, eight PCI Express*
(PCIe*) I/O ports
Dual Independent Bus (DIB) Architecture
The Dual Independent Bus (DIB) architecture was first implemented in the sixth-generation
processors from Intel and AMD. DIB was created to improve processor bus bandwidth and
performance. Having two (dual) independent data I/O buses enables the processor to access
data from either of its buses simultaneously and in parallel, rather than in a singular sequential
manner (as in a single-bus system). The second or backside bus in a processor with DIB is used
for the L2 cache, allowing it to run at much greater speeds than if it were to share the main
processor bus.
NOTE
The DIB architecture is explained more fully in Chapter 4, "Motherboards and Buses." To see the
typical Pentium II/III system architecture, see Figure 4.34.
Two buses make up the DIB architecture: the L2 cache bus and the processor-to-main-memory,
or system, bus. The P6 class processors from the Pentium Pro to the Celeron, Pentium II/III, and
Athlon/Duron processors can use both buses simultaneously, eliminating a bottleneck there. The
Dual Independent Bus architecture enables the L2 cache of the 1GHz Pentium III or Athlon, for
example, to run 15 times faster than the L2 cache of older Pentium and K6 processors. Because
the backside or L2 cache bus is coupled to the speed of the processor core, as the frequency of
processors increases, so will the speed of the L2 cache.
The key to implementing DIB was to move the L2 cache memory off of the motherboard and into
the processor package. L1 cache has always been directly a part of the processor die, but L2 was
larger and had to be external. By moving the L2 cache into the processor, the L2 cache could run
at speeds more like the L1 cache, much faster than the motherboard or processor bus. To move
the L2 cache into the processor initially, modifications had to be made to the CPU socket or slot.
There are two slot-based and three socket-based solutions that fully support DIB: Slot 1 (Pentium
II/III/Celeron), Slot A (Athlon), Socket 8 (Pentium Pro), Socket 370 (Pentium III/Celeron), and
Socket A (Athlon/Duron).
DIB also allows the system bus to perform multiple simultaneous transactions (instead of singular
sequential transactions), accelerating the flow of information within the system and boosting
performance. Overall DIB architecture offers up to three times the bandwidth performance over a
single-bus architecture processor.
Hyper-threading is where your processor pretends to have 2 physical processor cores, yet
only has 1 and some extra junk.
The point of hyperthreading is that many times when you are executing code in the
processor, there are parts of the processor that is idle. By including an extra set of CPU
registers, the processor can act like it has two cores and thus use all parts of the processor
in parallel. When the 2 cores both need to use one component of the processor, then one
core ends up waiting of course. This is why it can not replace dual-core and such
processors.
Hyper-Threading is a technology used by some Intel microprocessor s that allows a
single microprocessor to act like two separate processors to the operating system and
theapplication program s that use it. It is a feature of Intel's IA-32 processor
architecture.
With Hyper-Threading, a microprocessor's "core" processor can execute two (rather
than one) concurrent streams (or thread s) of instructions sent by the operating system.
Having two streams of execution units to work on allows more work to be done by the
processor during each clock cycle . To the operating system, the Hyper-Threading
microprocessor appears to be two separate processors. Because most of today's
operating systems (such as Windows and Linux) are capable of dividing their work load
among multiple processors (this is called symmetric multiprocessing or SMP ), the
operating system simply acts as though the Hyper-Threading processor is a pool of two
processors.
Intel notes that existing code will run correctly on a processor with Hyper-Threading but
"some relatively simple code modifications are recommended to get the optimum
benefit."
What Is a Core?
Each CPU “core” is actually a separate central processing unit, which is
the part of the CPU that actually does the work. For example, a dualcore chip may look like a single CPU chip, but it actually has two
physical central processing units on the chip.
Additional central processing units allow a computer to do multiple
things at once. If you’ve ever used a single-core CPU and made the
upgrade to a dual-core CPU, you should have noticed a significant
difference in how responsive your computer is.
For example, let’s say you’re extracting an archive file and browsing
the web at the same time. If you had a single-core CPU in your
computer, web browsing wouldn’t be very responsive. The single core
would have to split its time between web browsing and file-extraction
tasks. If you had a dual-core CPU with two cores, one core would work
on extracting the file while the other core did your web-browsing work.
Web browsing would be much faster and more responsive.
Whether you’re doing multiple things at once or not, your computer is
often doing system tasks in the background and you can benefit from
additional cores to keep the operating system responsive. Applications
can also be written to take advantage of multiple cores. For
example, Google Chrome renders each website with a separate
process. This allows Google Chrome to use different CPUs for different
websites rather than using a single CPU for all browser-related tasks.
Clock Speed vs. Cores
CPUs have a clock speed – think of it as how fast the CPU does work.
(That’s actually an imperfect analogy as the truth is a lot more
complicated, but it will have to do for now.)
For example, Intel’s Core i5-3330 processor has a clock speed of 3
GHz and is a quad-core processor, which means it has four cores. All
four cores in this Intel i5 processor are each running at 3 GHz.
Doubling The Cores Doesn’t Double The
Speed
Many computer programs are single-threaded, which means that their
work can’t be divided across multiple CPUs. They must each run on a
single CPU. This means that doubling the cores won’t double their
performance.
If you have a single-threaded application running on a 3 GHz quadcore CPU, that application will run at 3 GHz — not 12 GHz. It will use
one core and the other three cores will sit idle, waiting for other tasks
to perform.
Writing properly multithreaded applications that can scale across
several CPUs at once is actually a difficult problem in computer
science. It’s becoming a more crucial problem, as the future looks to
be computers with more and more cores instead of fewer cores at
faster and faster speeds.
Some applications can take advantage of multiple cores. Google
Chrome’s multi-process architecture allows it to perform actions across
several different cores at once. Some computer games can divide their
calculations across multiple separate cores at once.
However, most of the applications you use are likely single-threaded.
A quad-core CPU won’t run Microsoft Office twice as fast as a dual-core
CPU. If all you do is run Microsoft Office, the performance might be
extremely similar.
More cores help if you’re looking to do more at once or if you have a
multithreaded application that can take advantage of them. For
example, if you’re running severalvirtual machines while encoding
video, extracting files, and doing other CPU-demanding things on your
computer, an octo-core CPU may be able to keep up while even a
quad-core CPU may stumble under such load.
Dual Core, Quad Core & More
Phrases like “dual core,” “quad core,” and “octo core” all just refer to
the number of cores a CPU has:
o
Dual Core: Two cores.
o
Quad Core: Four cores.
o
Hexa Core: Six cores.
o
Octo Core: Eight cores.
o
Deca Core: Ten cores.
Dual Core, Quad Core & More
Phrases like “dual core,” “quad core,” and “octo core” all just refer to
the number of cores a CPU has:
o
Dual Core: Two cores.
o
Quad Core: Four cores.
o
Hexa Core: Six cores.
o
Octo Core: Eight cores.
o
Deca Core: Ten cores.
Controlling & Monitoring Cores
You can actually control which running programs can use a core from
the Windows task manager. Right-click a process on the Processes
pane and select Set Affinity.
You’ll be able to select which physical CPUs (cores) the application can
run on. You shouldn’t need to tweak this most of the time, although it
can be helpful when you want to restrict a demanding application to
certain cores or avoid bugs in old PC games.
From the task manager, you can also use the Performance tab to view
the usage of all your CPU cores.
Hyper-Threading
Intel CPUs use a technology referred to as “hyper-threading
technology.” With hyper-threading, each physical core presents itself
to the system as two logical cores. In the screenshot above, we’re not
using an octo-core CPU – we’re using a quad-core CPU with hyperthreading.
This improves performance to some degree, but a quad-core CPU with
hyper-threading is nowhere near as good as an octo-core CPU. You
still only have four physical cores, although some tricks allow them to
do a bit more work at once.
Dual Core
Dual-core refers to a CPU that includes two complete execution cores per physical processor. It has
combined two processors and their caches and cache controllers onto a single integrated
circuit (silicon chip). Dual-core processors are well-suited for multitasking environments because there are
two complete execution cores instead of one, each with an independent interface to the frontside bus. Since
each core has its own cache, theoperating system has sufficient resources to handle most compute
intensive tasks in parallel.
Multi-core is similar to dual-core in that it is an expansion to the dual-core technology which allows for more
than two separate processors.
Dual Core
A dual core processor for a computer is a central processing unit (CPU) that has two
separate cores on the same die, each with its own cache. It essentially is
two microprocessors in one. This type of CPU is widely available from many
manufacturers. Other types of multi-core processors also have been developed, including
quad-core processors with four cores each, hexa-core processors with six, octa-core
processors with eight and many-core processors with an even larger number of cores.
In a single-core or traditional processor, the CPU is fed strings of instructions that it must
order, execute, then selectively store in its cache for quick retrieval. When data outside
the cache is required, it is retrieved through the system bus from random access memory
(RAM) or from storage devices. Accessing these slows down performance to the
maximum speed that the bus, RAM or storage device will allow, which is far slower than
the speed of the CPU.
This situation is compounded when the computer user is multi-tasking. In this case, the
processor must switch back and forth between two or more sets of data streams and
programs. CPU resources are depleted, and performance suffers.
In a dual core processor, each core handles incoming data strings simultaneously to improve
efficiency. Just as two heads are better than one, so are two hands. When one core is
executing, the other can be accessing the system bus or executing its own code.
To utilize a dual core processor, the operating system must be able to recognize multithreading, and the software must have simultaneous multi-threading technology (SMT)
written into its code. SMT enables parallel multi-threading, wherein the cores are served
multi-threaded instructions in parallel. Without SMT, the software will recognize only one
core. SMT also is used with multi-processor systems that are common to servers.
A dual core processor is different from a multi-processor system. In the latter, there are two
separate CPUs with their own resources. In the former, resources are shared, and the cores
reside on the same chip. A multi-processor system is faster than a system with a dual core
processor, and a dual core system is faster than a single-core system, when everything else
is equal.
An attractive value of dual core processors is that they do not require new motherboards but
can be used in existing boards that feature the correct sockets. For the average user, the
difference in performance will be most noticeable during multi-tasking, until more software is
SMT aware. Servers that are running multiple dual core processors will see an appreciable
increase in performance.
MultiCore Processor
A multi-core processor is a single computing component with two or more independent
actual central processing units (called "cores"), which are the units that read and
execute program instructions.[1] The instructions are ordinary CPU instructions such as add, move
data, and branch, but the multiple cores can run multiple instructions at the same time, increasing
overall speed for programs amenable to parallel computing.[2] Manufacturers typically integrate
the cores onto a single integrated circuit die (known as a chip multiprocessor or CMP), or onto
multiple dies in a single chip package.
Processors were originally developed with only one core. A dual-core processor has two cores
(e.g. AMD Phenom II X2, Intel Core Duo), a quad-core processor contains four cores (e.g. AMD
Phenom II X4, Intel's quad-core processors, see i5, and i7 at Intel Core), a 6-core processor
contains six cores (e.g. AMD Phenom II X6, Intel Core i7 Extreme Edition 980X), an 8-core
processor contains eight cores (e.g.Intel Xeon E7-2820, AMD FX-8350), a 10-core processor
contains ten cores (e.g. Intel Xeon E7-2850), a 12-core processor contains twelve cores. A multicore processor implements multiprocessing in a single physical package. Designers may couple
cores in a multi-core device tightly or loosely. For example, cores may or may not share caches,
and they may implement message passing or shared memory inter-core communication
methods. Common network topologies to interconnect cores include bus, ring, two-dimensional
mesh, and crossbar.Homogeneous multi-core systems include only identical
cores, heterogeneous multi-core systems have cores that are not identical. Just as with singleprocessor systems, cores in multi-core systems may implement architectures such
as superscalar, VLIW, vector processing,SIMD, or multithreading.
Multi-core processors are widely used across many application domains including generalpurpose, embedded, network, digital signal processing (DSP), and graphics.
The improvement in performance gained by the use of a multi-core processor depends very much
on the software algorithms used and their implementation. In particular, possible gains are limited
by the fraction of the software that can be run in parallel simultaneously on multiple cores; this
effect is described by Amdahl's law. In the best case, so-called embarrassingly parallel problems
may realize speedup factors near the number of cores, or even more if the problem is split up
enough to fit within each core's cache(s), avoiding use of much slower main system memory.
Most applications, however, are not accelerated so much unless programmers invest a prohibitive
amount of effort in re-factoring the whole problem.[3] The parallelization of software is a significant
ongoing topic of research.
Terminology
The terms multi-core and dual-core most commonly refer to some sort of central processing
unit (CPU), but are sometimes also applied todigital signal processors (DSP) and system-on-achip (SoC). The terms are generally used only to refer to multi-core microprocessors that are
manufactured on the same integrated circuit die; separate microprocessor dies in the same
package are generally referred to by another name, such as multi-chip module. This article uses
the terms "multi-core" and "dual-core" for CPUs manufactured on the same integrated circuit,
unless otherwise noted.
In contrast to multi-core systems, the term multi-CPU refers to multiple physically separate
processing-units (which often contain special circuitry to facilitate communication between each
other).
The terms many-core and massively multi-core are sometimes used to describe multi-core
architectures with an especially high number of cores (tens or hundreds). [4]
Some systems use many soft microprocessor cores placed on a single FPGA. Each "core" can
be considered a "semiconductor intellectual property core" as well as a CPU core[citation needed].
Advantages[edit]
The proximity of multiple CPU cores on the same die allows the cache coherency circuitry to
operate at a much higher clock-rate than is possible if the signals have to travel off-chip.
Combining equivalent CPUs on a single die significantly improves the performance of cache
snoop (alternative: Bus snooping) operations. Put simply, this means that signalsbetween
different CPUs travel shorter distances, and therefore those signals degrade less. These higherquality signals allow more data to be sent in a given time period, since individual signals can be
shorter and do not need to be repeated as often.
Assuming that the die can physically fit into the package, multi-core CPU designs require much
less printed circuit board (PCB) space than do multi-chip SMP designs. Also, a dual-core
processor uses slightly less power than two coupled single-core processors, principally because
of the decreased power required to drive signals external to the chip. Furthermore, the cores
share some circuitry, like the L2 cache and the interface to the front side bus (FSB). In terms of
competing technologies for the available silicon die area, multi-core design can make use of
proven CPU core library designs and produce a product with lower risk of design error than
devising a new wider core-design. Also, adding more cache suffers from diminishing returns. [citation
needed]
Multi-core chips also allow higher performance at lower energy. This can be a big factor in mobile
devices that operate on batteries. Since each and every core in multi-core is generally more
energy-efficient, the chip becomes more efficient than having a single large monolithic core. This
allows higher performance with less energy. The challenge of writing parallel code clearly offsets
this benefit.[7]
Disadvantages[edit]
Maximizing the utilization of the computing resources provided by multi-core processors requires
adjustments both to the operating system (OS) support and to existing application software. Also,
the ability of multi-core processors to increase application performance depends on the use of
multiple threads within applications. The situation is improving: for example the Valve
Corporation's Source engine offers multi-core support,[8][9] and Crytek has developed similar
technologies for CryEngine 2, which powers their game, Crysis.Emergent Game
Technologies' Gamebryo engine includes their Floodgate technology,[10] which simplifies multicore development across game platforms. In addition, Apple Inc.'sOS X, starting with Mac OS X
Snow Leopard, and iOS starting with iOS 4, have a built-in multi-core facility called Grand Central
Dispatch.
Integration of a multi-core chip drives chip production yields down and they are more difficult to
manage thermally than lower-density single-chip designs. Intel has partially countered this first
problem by creating its quad-core designs by combining two dual-core on a single die with a
unified cache, hence any two working dual-core dies can be used, as opposed to producing four
cores on a single die and requiring all four to work to produce a quad-core. From an architectural
point of view, ultimately, single CPU designs may make better use of the silicon surface area than
multiprocessing cores, so a development commitment to this architecture may carry the risk of
obsolescence. Finally, raw processing power is not the only constraint on system performance.
Two processing cores sharing the same system bus and memory bandwidth limits the real-world
performance advantage. It has been claimed[by whom?] that if a single core is close to being
memory-bandwidth limited, then going to dual-core might give 30% to 70% improvement; if
memory bandwidth is not a problem, then a 90% improvement can be expected;
however, Amdahl's law makes this claim dubious.[11] It would be possible for an application that
used two CPUs to end up running faster on one dual-core if communication between the CPUs
was the limiting factor, which would count as more than 100% improvement.
Core-2
Core 2 is a brand encompassing a range of Intel's consumer 64-bit x86-64 single-, dual-, and
quad-core microprocessors based on theCore microarchitecture. The single- and dual-core
models are single-die, whereas the quad-core models comprise two dies, each containing two
cores, packaged in a multi-chip module.[1] The introduction of Core 2 relegated the Pentium brand
to the mid-range market, and reunified laptop and desktop CPU lines, which previously had been
divided into the Pentium 4, Pentium D, and Pentium Mbrands.
The Core 2 brand was introduced on 27 July 2006,[2] comprising the Solo (singlecore), Duo (dual-core), Quad (quad-core), and in 2007, the Extreme (dual- or quad-core CPUs
for enthusiasts) subbrands.[3] Intel Core 2 processors with vPro technology (designed for
businesses) include the dual-core and quad-core branches.[4]
Diffrence Between Dual and Quad core
Key Difference: A dual-core processor is a type of a central
processing unit (CPU) that has two complete execution cores. Quadcore processors have four independent central processing units that
can read and execute instructions.
The constant evolution of computers requires it to be faster, stronger and better. This requirement
has been getting companies to bud heads trying to figure out ways to make the computers faster
and more power processors. This has given birth to technologies such as dual-core and quadcore processors. Dual-core and quad-core are also known as multi-core processors.
A dual-core processor is a type of a central processing unit (CPU) that has two complete
execution cores. Hence, it has the combined power of two processors, their caches and the
cache controllers onto a single chip. This makes the dual-core processors well-suited for
multitasking. Dual-core processors have two cores that have an independent interface to the
frontside bus. Each core has its own cache. This allows the operating system to have sufficient
resources to handle intensive tasks in parallel.
Dual Core is a generic name for any processor with two cores from any manufacture. However,
due to marketing and Intel’s predominance in the CPU market, dual core has become
synonymous with Intel Pentium Dual Core. It may sometimes also be used to refer to Intel’s Core
2 Duo line. AMD, the main competitor of Intel, also had a dual-core processor under the x2 brand.
Quad-core processors are the next step after dual-core. True to
its name quad-core refers to processors having four independent central processing units that
can read and execute instructions. Quad-cores actually comprise two dual-core processors,
where processor 1 and 2 would share the same memory cache, while processors 3 and 4 would
share one. Incase processor 1 needs to communicate with processor 3; it would have to be
through an external frontside bus. Both Intel and AMD have released quad-core processors.
Though quad-core is a faster and better technology, it also has some limitations. The true
performance of quad-core is often lacking due to external problems. One such problem is heat,
each core generate a lot of heat while running, so four cores requires powerful cooling measure
such as liquid cooling (which are harder to implant) or to reduce the total speed of the core. This
provides a dip in the performance of the cores. Another problem that arises is the hardware,
though the processors have been upgraded, the hardware has not yet caught up to the
processor. Because of this, during the execution of heavy tasks, the data of the processors would
become more congested.
Even though there are minor limitations with the quad-core, it is soon expected to be dealt with.
The supporting hardware and software are soon expected to catch up with these cores. Other
multiple-core processors are also in the works including a hexa-core processor, which contains
six cores and an octa-core processor, which contains eight cores.
Rapid Execution Engine
As we mentioned in our initial coverage of the CPU, the Pentium 4's Arithmetic Logic Units
(ALUs) operate at twice the core clock frequency. This means that on a 1.4GHz Pentium 4, the
ALUs are effectively running at 2.8GHz and on the 1.5GHz Pentium 4 demo we saw 6 months
ago, the ALUs were effectively running at an impressive 3.0GHz. Intel refers to this feature as the
NetBurst architecture's Rapid Execution Engine.
We predicted that this would give the Pentium 4 the clear advantage in Integer performance,
however from our recent discussions with Intel, it seems as if the main reason for clocking the
integer ALUs at twice the core frequency was to make up for the lower IPC of the NetBurst
architecture.
While we can't release performance numbers today (those will have to wait until the CPU is
actually released), remember that the Rapid Execution Engine might be necessary in order to
make sure that the Pentium 4 can outperform the Pentium III in integer applications.
The biggest question most of you all had when we first mentioned the 2X clocked ALUs back in
February was whether or not we'd see chips advertised at 3GHz just because their ALUs were
effectively running that high or whether we'd see some processors with normally clocked ALUs
and others with 2X ALUs. Our understanding of the matter is that Intel won't be doing anything
like that, and the feature is simply a part of the NetBurst architecture. It would be very misleading
if Intel attempted to pursue either of those avenues of marketing, and chances are that they
won't.
Advanced Dynamic Execution
The advanced dynamic execution engine is a very deep out-of-order speculative
execution engine that keeps the execution units executing instructions. It also includes an
enhanced branch prediction algorithm that has the net effect of reducing the number of
branch prediction
Cache Memory
Cache (pronounced cash) memory is extremely fast memory that is built into a
computer’s central processing unit (CPU), or located next to it on a separate chip. The
CPU uses cache memory to store instructions that are repeatedly required to run
programs, improving overall system speed. The advantage of cache memory is that the
CPU does not have to use the motherboard’s system bus for data transfer. Whenever data
must be passed through the system bus, the data transfer speed slows to the
motherboard’s capability. The CPU can process data much faster by avoiding the
bottleneck created by the system bus.
As it happens, once most programs are open and running, they use very few resources.
When these resources are kept in cache, programs can operate more quickly and
efficiently. All else being equal, cache is so effective in system performance that a
computer running a fast CPU with little cache can have lower benchmarks than a system
running a somewhat slower CPU with more cache. Cache built into the CPU itself is
referred to as Level 1 (L1) cache. Cache that resides on a separate chip next to the CPU is
called Level 2 (L2) cache. Some CPUs have both L1 and L2 cache built-in and designate
the separate cache chip as Level 3 (L3) cache.
Cache that is built into the CPU is faster than separate cache, running at the speed of the
microprocessor itself. However, separate cache is still roughly twice as fast as Random
Access Memory (RAM). Cache is more expensive than RAM, but it is well worth
getting a CPU and motherboard with built-in cache in order to maximize system
performance.
Disk caching applies the same principle to the hard disk that memory caching applies to
the CPU. Frequently accessed hard disk data is stored in a separate segment of RAM in
order to avoid having to retrieve it from the hard disk over and over. In this case, RAM is
faster than the platter technology used in conventional hard disks. This situation will
change, however, as hybrid hard disks become ubiquitous. These disks have built-in flash
memory caches. Eventually, hard drives will be 100% flash drives, eliminating the need
for RAM disk caching, as flash memory is faster than RAM.
his memory is generally divided into different level. In the following figure we see the process
flow:
Let us suppose that the system has cache of three levels (level means that overall cache memory
is split into different hardware segments which vary in their processing speed and memory). From
RAM data is transferred into cache of 3rd level (L3 cache). L3 cache is a segment of overall cache
memory. L3 cacheis faster than RAM but slower then L2 cache. To further fasten up the process
cache of second order L2 cache are used. They are located at immediate vicinity of processor.
But in some of the modern processors L2 cache is inbuilt making the process faster. It should be
noted that it is not necessary that a system has 3 levels of cache; it might have 1 or 2 level of
cache. At the core level is cache of first level that is L1 cache memory. The commonly used
commands/instructions/data is stored in this section of memory. This is built in the processor
itself. Thus this is fastest of all the cache memory.
PROCESS FLOW
So whenever the processor needs to perform an action or execute any command then it first
checks the state of the data registers. If the required instruction/data is not present over there,
then it looks in the first level of cache memory – L1, and if there also data is not present it further
goes to second and further third level of cache memory. Whenever the data needed by processor
is not found in the cache it is known as CACHE MISS and it leads to delay in the execution thus
making the system slow. If the data is found in cache memory it is known as CACHE HIT.
If the data needed is not found in any of the cache memory, the processor checks in RAM. And if
this also fails then it goes to look onto the slower storage device.
So the above process can be graphically summarized as:
Memory
BIOS ROM
The BIOS (Basic Input/Output System) program runs when the PC is
started.It has a number of functions:

To check the status of the motherboard circuitry


To prepare the system ready for the DOS (Disk
Operating System) — normally Windows or Linux — to
boot and take over
To allow access to the computer's settings stored in
CMOS memory
BIOS chips are easily spotted because they usually have "BIOS"
written on them as part of a manufacturer's label. BIOS ROMs
usually sit in a socket, allowing them to be easily removed (with a
special chip extraction tool) if faulty.
CMOS Memory
When people first started building microcomputers there were two
technologies available for digital circuit design. The first, TTL
(Transistor-Transistor Logic), was fast but consumed lots of power.
The second, CMOS (Complimentary Metal Oxide Semiconductor),
was slower but used less power and could work at a range of
voltages. CMOS was also more sensitive to static electricity.
Computer circuits tended to use TTL circuitry (because they needed
speed) and CMOS was used for toys (where batteries were the main
power source).
When the PC motherboard needed a non-volatile memory to store
system settings, designers used a CMOS SRAM powered by battery.
This chip became known as "the CMOS Memory".
Since then CMOS circuitry has improved to the stage where it has
superseded TTL and today most parts of a PC are built using CMOS.
However, for historical reasons, this non-volatile RAM is still called
"the CMOS Memory" and its contents are referred to as "CMOS
Settings".
The CMOS Memory used to be powered by a lithium watch battery,
typically a CR2032. This battery also powered the PC's real-time
clock (RTC).
Modern motherboards use Flash ROM for CMOS settings instead.
Cache Memory
Cache memory sits between the CPU and the main memory.
A cache controller monitors the addresses that are requested by the
CPU and predicts which memory will be required in the future.
Data is read into the cache memory in advance, allowing the
computer to obtain data far more quickly from the cache than from the
main memory. Tagsare used identify where cached data originated.
Cache is built from SRAM.
L1 & L2 cache
Level 1 (L1) cache memory is now typically built into the main
processor circuit.
Level 2 (L2) cache memory was commonly on the motherboard but
since the Pentium II has been built into the same case as the
processor circuit (although often mounted separately). Many
motherboards now have L3 cache.
Main memory
SIMMs
SIMMs (Single Inline Memory Module) were used from the 286 up
to the early Pentiums. These were designed to make the process of
installing memory easier and faster. There were two sizes: 30-pin (8
bits wide) and 72pin (32 bits wide). They needed to be inserted at a
45 angle and tilted into an upright position. SIMMs often needed to
be installed in banks (groups of 2 or 4) to ensure that memory widths
matched the processor's data bus width.
Parity
Parity uses an extra bit as an error-checking bit for every 8 bits.
Thus 30-pin SIMMs 'with parity' are 9-bit and 72-pin SIMMs 'with
parity' are 36-bit.
FPM, EDO and bursts
EDO (Extended Data Outburst) DRAM is around 30% faster than
standard Fast Page Mode (FPM) DRAM.
DIMMs
DIMMs (Dual Inline Memory Module) were introduced with Pentium
class processors and come in a variety of styles and sizes. Small
outline DIMMs (SoDIMMs) are used for laptops.
Unlike SIMMs they are inserted vertically, forcing locking clips into
position. Open the locking clips to eject the DIMM.
SDRAM
SDRAM (Synchronous DRAM) is synchronised to the system's
Front-Side Bus (FSB) clock pulse. This allows it to work more quickly
than EDO DRAM.
DDR & DDR2
DDR (Double Data Rate) SDRAM works at twice the speed of
conventional SDRAM and is identified by its effective clock speed
(e.g. DDR533 actually works at 266 MHz).
To make speed comparisons easier, DDR RAM is rated by its peak
bandwidth in the form of a "PC" number (e.g. PC 2700 transfers 2700
MB/s).
DDR-2 is a faster form of DDR memory, measured in a similar way to
DDR.
ECC
Error-Correcting Code (ECC) uses parity bits to perform a more
sophisticated type of error-checking. DIMMs that support ECC are
known as ECC memory and thus provide 72-bit storage.
Unbuffered or Registered
Unbuffered DDR memory allows control signals to pass quickly to
RAM, which can be a problem in systems with large amounts of
memory. Registered memory adds extra circuitry and eases this
problem but at a financial cost.
Dual channel
Many motherboards support dual channel memory. This gives a
significant speed increase by accessing two DIMMs simultaneously
but requires performance-matched DIMMs.
Rambus (RIMMs)
Rambus was a system designed to give exceptional memory access
speed. It was used by Intel on early Pentium 4 systems.
RIMMs are 184-pin boards similar to DIMMs in appearance, with heat
spreader cases.
Continuity Connectors
RIMMs transfer only 16 bits at a time but at very high speed. The
high-speed bus design requires all slots to be populated, so 'dummy'
RIMMs known ascontinuity connectors must be used in any empty
slots.
Motherboards
Chipset
North & South Bridge
The PCI bus (see next section) requires a pairs of chips to manage
communication between parts of a PC. These chips are known as
the North Bridge (ormemory controller) and South Bridge (or I/O
controller).
The bridges are collectively known as the motherboard chipset (a
term that sometimes includes the CPU) and this chipset forms the
heart of a modern motherboard. Some chipsets include extra
facilities, such as onboard graphics or wireless networking (e.g.
Intel's Centrino chipset).
Older desktop Pentium designs feature a three-chip chipset: the third
IC interfaces the ISA bus to the PCI bus.
Early bus architecture
ISA
Industry Standard Architecture (ISA) was the original PC bus.
Initially it carried an 8-bit data bus signal (synchronised to a 4MHz
clock). When the AT was introduced this was widened to 16 bits at
8MHz.
Attempts to improve or replace ISA
When IBM released its PS/2 in 1987 it tried to introduce a major
redesign: the MicroChannel Architecture (MCA) bus. This 16 / 32
bit design was completely incompatible with ISA and failed to catch
on.
Extended ISA (EISA) used taller slots to extend the system to a 32bit data bus (still at 8MHz) but it was not widely supported.
Graphics cards used the Video Electronics Standards Association
(VESA) local bus extension. This extended the ISA slot to create a
32-bit, higher-speed bus.
PCI bus
How the PCI bus operates
The Peripheral Component Interconnect (PCI) local bus design
creates a main data highway between the processor and other
devices.
PCI expansion cards are configured by the
motherboard's PnP (plug 'n' play) system, allocating resources (IRQ,
I/O address) automatically. The PCI bus operates its own DMA
controller, allowing large quantities of data to be transferred quickly
between devices without the CPU's involvement.
Originally the PCI expansion slots were at the heart of the PCI bus
but this shifted to the south bridge as manufacturers introduced
dedicated north-south bridge local buses (as illustrated on the Intel
i810E chipset above).
The important thing about the PCI bus is that it is independent of the
CPU's system bus; it can expand to accommodate new processor
designs and new peripherals. The bus transfers 132 MBps using a
32-bit bus and 264 MBps using a 64-bit bus by subdividing the main
bus clock (33MHz).
There are a number of different version numbers of PCI, which refer
to speed improvements. When selecting PCI cards it is important to
ensure that the versions match for maximum compatibility and speed.
The connection between north bridge and CPU is along a front-side
bus (FSB). Alternative designs, such as HyperTransport, offer very
fast connection between the north bridge and CPU.
AGP
Accelerated Graphics Port (AGP) modified the PCI bus design to
handle the high data traffic associated with three-dimensional
graphics.
AGP provides a 32-bit video channel that runs at 66MHz in
basic 1X video mode. AGP also supports three high-speed modes
that include 2X (5.33 MBps),4X (1.07 GBps), and 8X (2.1 GBps).
AGP provides a direct channel between the AGP graphic controller
and the system's main memory, instead of using the expansion buses
for video data. This removes the video data traffic from the PCI
buses. The speed provided by this direct link permits video data to be
stored in system RAM instead of in special video memory.
8X employs a lower supply voltage (0.8) than the 2X and 4X
specifications. When upgrading an AGP card or system board
containing an AGP slot, you should always consult the system board
and AGP adapter card's documentation to verify their compatibility
with each other.
AMR & CNR
Audio Modem Risers (AMR) and Mobile Daughter Card
(MDC) were sometimes used to connect sounds cards and modems.
These have been replaced by a new design called
the Communication and Networking Riser (CNR) card. This
includes support for V.90 modems, multi-channel audio, telephonebased dial-up networking, USB devices, and 10/100 Ethernet-based
LAN adapters.
PCI Express
PCI Express (PCIe) is a major redesign that uses high-speed serial
signalling arranged in lanes. This allows different sized cards to be
used that may or may not require high-speed transfers.
All PCI Express slots must support x1 (single-lane) connections — so
you can plug a x1 card into a x16 slot if necessary. Smaller cards can
be placed in larger slots (but larger cards cannot physically fit into
smaller slots).
All interrupts and control signals are encoded into the serial data
stream.
The photo below shows (top to bottom) a x4, x16, x1, x16 and a
normal PCI slot.
CPU Technologies
Processor cores
What is a core?
The core of the processor is the part that decodes and executes
instructions. On early processors this would describe the whole CPU
but over the last 20 years processors have gained builtin cache memory and cache controllers.
Operating speed and power requirements are affected by transistor
size; the construction process size of transistor circuits is quoted to
give an idea of the advance in technology: Pentium III processors
used 180nm technology, whereas modern Intel Core 2 CPUs are
65nm.
Manufacturers usually use a codename to identify a particular design
of processor core, and this typically indicates the process size (e.g.
90nm) and operational efficiency.
core name
process processor
Willamette
180nm
Pentium 4
478
256 KB
Northwood
130nm
Celeron
478
128 KB
Pentium 4
478
512 KB
Celeron D /
P4
478
256 KB /
1MB
Celeron D /
P4 (5xx)
775
256 KB /
1MB
Prescott 2M 90nm
Pentium 4
(6xx)
775
2 MB
Cedar Mill
65nm
Pentium 4
(6xx)
775
2 MB
Smithfield
90nm
Pentium D
(8xx)
775
2 MB
Presler
65nm
Pentium D
(9xx)
775
4 MB
Yonah
65nm
Core Duo /
Solo
775
4 MB
Prescott
90nm
socket
typical L2
cache
core name
process processor
Conroe
65nm
Core 2 Duo
socket
775
socket
typical L2
cache
4 MB
typical L2
cache
core name
process processor
Thoroughbred
130nm
Athlon XP
A
256 KB
Barton
130nm
Athlon XP
A
512 KB
Palermo
90nm
Sempron
754
128 KB
Clawhammer
130nm
Athlon 64
754
1 MB
Newcastle
130nm
Athlon 64
754
512 KB
Athlon 64
939
512 KB
Sledgehammer 130nm
Athlon
64/FX
939
1 MB
Winchester
90nm
Athlon 64
939
512 KB
Venice
90nm
Athlon 64
939
512 KB
Manchester
90nm
Athlon 64
X2
939
1 MB
Toledo
90nm
Athlon 64
X2
939
2 MB
Core names are like version numbers; stepping numbers indicate
revisions or bug-fixes. It is important to match core & stepping in
multi-processor systems.
The diagram below shows the architecture of a Conroe core:
Microcode
x86 processors are CISC (complex instruction set computer) designs,
which means that some instructions are built from a combination of
others. These combinations are stored as microcode inside the
processor. There has been a shift away from CISC technology to
wards RISC (reduced instruction set) commands in newer CPUs.
RISC instructions can be more easily pipelined, allowing one
instruction to be executed while another is being decoded.
Hyperthreading
Threads are independent parts of a computer program. Multi-tasking
operating systems (e.g. Windows or Linux) work by allocating each
thread a certain amount of "CPU time" in which to execute some
instructions. This means that they can run dozens of programs "at
the same time".
Multi-processor systems allow the OS to literally run two or more
program threads simultaneously on different CPUs. This means that
there is less competition for CPU time and therefore the computer
should operate more quickly. However, multiprocessor systems are
expensive.
Hyper-Threading Technology (HTT) was introduced by Intel to give
a cost-effective compromise. By duplicating some of the parts of the
main core it pretends to be two processors. This gives a small speed
increase (up to 30%).
Dual Core & multi-core
Dual core designs have two cores on a single chip, sometimes
sharing L2 cache memory and always sharing bus interfaces. A dualcore chip is not as good as having two processors; however it gives
typically 25%–75% faster performance than a single core processor.
The Athlon 64 X2 and Pentium D were the first dual-core processors
released for the PC, followed by the Intel Core Duo, Core 2 Duo and
AMDAthlon FX60. Intel has released a four-core Core 2
Quadro processor.
Instruction set
The x86 family of processors has a common set of instructions that
the processor recognises. This instruction set has been extended
on several occasions. The first major revision was with the 386
processor, which introduced special 32-bit instruction codes.
MMX
Early processors could perform integer arithmetic only (i.e.
calculations involving whole numbers). Manufacturers soon added
Floating-Point Units (FPU) to process numbers with decimal points.
These were quickly integrated within the main processor core.
The Pentium MMX (Matrix Math Extensions but more commonly
misnamed Multi-Media eXtensions) introduced extra instructions to
make floating-point maths easier, especially when manipulating
several numbers at once. This concept is called SIMD (Single
Instruction, Multiple Data) and means that graphics and sound
software can run more quickly.
SSE / SSE2 / SSE3
AMD fought back with an expanded MMX instruction set
called 3DNow!
Intel created their own version of 3DNow called SSE (Streaming
SIMD Extensions), adding 70 new maths instructions. This was taken
further with the Pentium 4's SSE2 and SSE3 extensions.
A multimedia program that supports SSE3 can run from 10% to 100%
faster on an SSE3-compatible processor.
Protected execution
The binary codes used for instructions are indistinguishable from
those used for storing data. If a computer programmer issues an
incorrect instruction it is possible to accidentally start executing data
codes as if they were proper instructions. This is surprisingly
common and leads to unexpected results and crashed software.
This flaw is used by hackers to create buffer overflow attacks.
These take advantage of programming errors by disguising instruction
codes as data. Thus, when the data is accidentally executed, the
CPU carries out the instructions set by the hacker. Most "critical"
software patches are aimed at fixing this kind of vulnerability.
The Athlon 64 introduced NX (No eXecute) technology, which allows
the processor to mark memory addresses as containing nonexecutable code. Thus the processor can tell if it has strayed into
data and will refuse to execute it. This gives better protection against
buffer overflow attacks. Intel recently introduced, XDB (eXecute
Disable Bit), which does the same thing.
Speed
Clock speed
The processing of instructions in a CPU is governed by a single
repeating signal — the clock — that synchronises the movement of
data within the CPU.
It used to be easy to measure the performance of a processor by
looking at its clock frequency (also called clock speed or clock
rate). However that is no longer the case...
There is a maximum limit to the clock frequency: this is determined by
the signalling voltage and the transistor design. If a clock goes too
fast then internal buses will change state too quickly and numeric
codes will not be read properly.
VRM
Lower signalling voltages mean faster clock rates, because the signal
can slew to the desired levels more quickly. To ensure that the core
has the appropriate level of voltage a Voltage Regulator Module
(VRM) is required.
ATX motherboards have VRM built in. Older, AT-based systems do
not get a 3V power line and therefore need more hefty VRMs; these
sometimes plug in on a separate card beside the processor.
Real speed vs. actual speed
However, AMD started producing CPUs that did more work in every
clock cycle. Thus a 1.8 GHz Athlon would carry out the same number
of instructions per second as a 2.4 GHz Pentium III. Therefore AMD
started identifying their chips by the equivalent speed: the 1.8GHz
Athlon was sold as the "Athlon 2400+".
Recently Intel has developed a similar problem. The 2.2 GHz
Pentium 4M for laptops is outperformed by the 1.6 GHz Pentium M
processor. Intel has now abandoned the use of clock speeds to
designate processor "quality" and has adopted a proprietary
numbering system.
The only way to judge a processor now is to
compare benchmark speed tests, such as those at
www.tomshardware.com
Throttling
CPUs typically operate at a constant speed and this can mean
excessive power use when they are idle. This can be a major factor
in laptops.
Processor throttling is the act of lowering the processor workload or
slowing it down to reduce power consumption. This can be done
automatically by some type of CPU or by special software. The
Pentium M has TM1 and TM2 thermal monitoring which respectively
add no-operation (NOP) instructions (to slow execution) and lower the
internal clock multiplier.
Overclocking
Overclocking is the process of increasing the processor clock
frequency to the maximum possible level. This can have a number of
side effects:


Increased temperature, requiring better cooling
systems
Occasional crashes due to illegal instruction codes
Many processors can be overclocked and there are numerous
websites dedicated to statistics regarding relative performance and
stability.
CPUs
What is a computer?
Mechanical calculating machines have existed for many centuries,
albeit in crude form. The Industrial Revolution introduced
programmable machines that could carry out a sequence of tasks by
following a shaped gear, or pegs in a board or wheel. It was Charles
Babbage who first thought of putting the two together, to create a
programmable calculating machine: the computer.
CPU
The heart of a modern electronic computer is the central processing
unit (CPU or processor): a calculator that can be controlled by
numeric machine codes representing instructions (e.g. add,
subtract).
The microprocessor is a CPU circuit contained within a silicon chip.
Main Memory
The CPU is fed a sequence of machine codes from main memory.
This memory is formed from ROM and RAM chips. Each machine
code occupies a numbered location — an address — in the memory.
Codes are usually read in consecutive order.
I/O Circuitry
The CPU can also send data to-and-from external devices (e.g.
keyboard, disk drive, video card) through input / output circuitry.
This design of computer (CPU, memory and I/O) is known as von
Neumann architecture.
Inside a CPU
Early CPUs are split into three main sections:
ALU (Arithmetic & Logic Unit) — this is a circuit that performs
calculations and logical comparisons.
Registers — numbers that are being processed are stored here.
Each register is "word"-sized and can be accessed at high-speed.
Instruction Decoder — this controls all other parts of the CPU,
sending signals in preset patterns to shift data between registers, the
ALU and the main data and address buses.
A word is defined by the size of the CPU's registers. This
measurement is also used to describe the capability of the processor.
Thus a "16-bit CPU" has 16bit-sized registers. The external data
bus is often the same width as the registers.
The external address bus will have a different width, depending on
the amount of memory that it may access.
Internal cache
Cache memory is a higher-speed memory device located between
the CPU and main memory. This allows data to be pre-fetched into
cache memory and read faster than main memory would allow. The
cache closest to the processor is called level 1 (L1) cache and is
often built within the CPU circuit itself. Level 2 (L2) cache used to be
located on the motherboard but is now integrated onto the processor
circuit board.
History
Things have come a long way since the Intel 4004, the first
microprocessor.
The Intel 8086 family of processors (known as x86) was so
successful that a number of other chip manufacturers made their own
versions of these chips. Companies like Cyrix, AMD and IBM
produced 286, 386 and 486 processor clones. To counter this Intel
trademarked the next generation chip with the name Pentium:
competitors chose different names (K5, 5x86, etc).
386 & 486
The 386 processor introduced wider 32-bit internal registers and a
wide range of new instructions to take advantage of them. Programs
written to use these new instructions were labelled as i386 compatible
(also IA-32). The 386 also included memory management circuits.
The 486 improved on this.
Pentium
The original Pentium was essentially two 486 processors in one chip
and contained 16KB of L1 cache (one 8KB cache for instructions or
code, and another for data). It came in a 273-pin Pin Grid Array
(PGA) package (known as Socket 4) and operated at 60 MHz. It was
powered at 5V and generated enough heat to require a CPU cooling
fan.
The second generation Pentium came in a 296-pin Staggered Pin
Grid Array (SPGA) package (Socket 7) in speeds from 75 to 166
MHz. The power-supply voltage level dropped to 3.3V, consuming
less power and provide faster operating speeds. This design used an
internal clock multiplier: this meant that the insides of the chip ran
much faster than the main data bus that was attached to the
processor. (This bus is called the Front-Side Bus or FSB).
The Pentium also introduced a 64-bit external data bus. The internal
design remained 32-bit, but the double-width interface allowed the
CPU to move data in and out more quickly.
The main competitors to the Pentium were the AMD K5 and
Cyrix 5x86, and they were designed to use Socket 7. The AMD
processor was designed in such a way that more processing was
done in each clock cycle: in other words an AMD chip running at 100
MHz might perform as well as an Intel Pentium at 133 MHz. To solve
this confusion, AMD chips were rated by the equivalent P-speed (e.g.
P133 = equivalent to Pentium 133).
Pentium MMX
The third generation Pentium also used the 296-pin SPGA
arrangement (Super Socket 7) and was produced in 166 – 233MHz
speeds with 32KB cache. These devices had 57 extra instruction
codes for multimedia work and were known as Pentium
MMX processors. The K6 and MII are, respectively, the AMD and
Cyrix equivalents of the MMX processor.
Pentium Pro
The Pentium Pro was designed for multi-processor systems. It used
a 387-pin PGA (Socket 8) package; came with 16KB L1 cache and
an onboard 256 or 512KB L2 cache
Pentium II / III class
Pentium II
The Pentium II used a new Single-Edge Contact (SEC) cartridge
(also known as SECC). The 242-contact design is called Slot 1 and
requires a special Fan Heat Sink (FHS) module and fan. The
cartridge contains the Pentium II processor core (incorporating 32KB
L1 cache) and 512KB L2 cache.
The K6-2 was AMD's answer to the Pentium II and it added 21 further
instructions to support multimedia work. It still used Super Socket 7.
Pentium III & Celeron
The original Pentium III was a Pentium II core with 512KB L2 cache.
Speed increased to 600MHz, including a 100MHz front-side bus
(FSB). Early models used Slot 1 but later versions switched to the
FC-PGA Socket 418 package.
The Celeron was designed as a cheap version of the Pentium II & III.
Originally the main difference was a lack of cache memory but later
Celerons added cache. The chips originally came in Slot 1 designed
but soon switched to Plastic PGA (PPGA) Intel Socket 370 packages.
AMD Athlon & Duron
The K7 Athlon originally ran at 500 MHz with 128KB L1 cache and a
512KB L2 cache. Early Athlons used Slot A, (mechanically identical
to Slot 1 but different electrical connections), however, they soon
switched to using Socket A.
Duron was introduced as a cheap alternative, mimicking the
Celeron. It also uses Socket A.
Pentium Xeon
The Xeon is the replacement for the Pentium Pro range: essentially a
special version of the Pentium II for multiprocessor systems. They
also featured up to 2MB of internal cache memory. Up to 32 Xeon
processors could be mounted in a single system.
Pentium 4 class
Pentium 4
The early Pentium 4 used 423-pin PGA (Socket 423) but later
models employed the improved Socket 478 package.
The 64-bit external data bus of the Pentium design expanded to 128
bits and the minimum FSB speed increased to 400MHz. The core
voltage dropped to 1.7V, allowing even faster execution — but the
design requires a separate 12V power supply to the motherboard.
Athlon XP & Sempron
The Athlon XP range covers 1500 to 3000 (note that numbers are
not MHz but Pentium speed equivalents). The Duron and lower-end
Athlon XPs were renamed Sempron.
Pentium 4 HT ("Prescott")
Hyperthreading is Intel's name for a design that duplicates many
parts of the processor, allowing two program threads to run
simultaneously, but not as quickly as a full dual core.
Xeon & Athlon MP
The (P4-based) Xeon and Athlon MP processors are designed for
multiprocessor systems.
Pentium M
The Pentium M is a variant of the Pentium 4 designed specially for
laptops. It significantly outperforms the P4 at the same clock speed.
The Pentium M forms part of the Intel Centrino chipset, along with
wireless networking support chips.
The shift to 64-bit
Itanium & Itanium 2
The Itanium was a drastic departure from the x86 design. A new,
more efficient 64-bit instruction set was introduced (known as IA-64)
but this was totally incompatible with i386 programs. Hence the
processor did not catch on, and is only used in high-end server
systems. The Itanium is mounted in a Pin Array Cartridge (PAC).
AMD Athlon 64 & Sempron/64
The Athlon 64 also featured a new 64-bit instruction set but it
maintained full compatibility with the older i386 codes. This design is
called AMD64, x86-64or more commonly x64.
The Athlon 64 introduces a new processor socket: Socket 754, which
looks similar to the newer Pentium 4 Socket 478 and Xeon Socket
603 and uses the same type of mPGA connectors. As with the
Pentium 4 processor, motherboards for the Athlon 64 also require the
ATX12V connector to provide adequate 12V power.
The Sempron/64 is intended to cover the lower end of the Athlon
market and fits in socket 754.
Pentium 4 EM64T, Celeron D
Intel knew they were in trouble when the Athlon 64 appeared.
Therefore they introduced versions of the P4 and Celeron that
support the x86-64 instruction set. However, they refer to these
instructions as EM64T codes. Note that Celeron D does not contain
dual cores.
Athlon64 X2, Pentium D & Pentium M Dual Core
These feature dual cores: multiprocessor systems can be expensive
but an alternative is to mount two processor cores in the same
package, sharing some circuitry.
Xeon EM64T & AMD Opteron
The Xeon EM64T supports the x86-64 instruction set.
The Opteron is AMD's equivalent to the Xeon EM64T and is aimed at
the server market.
AMD Turion 64
The Turion 64 is designed to compete with the Pentium M in the
laptop market. This uses the new Socket S.
Last of the 32-bit processors
Intel Core Duo
The 32-bit processor market is not dead. In January 2006 Intel
announced the Core Duo processors that would be used in laptops
(branded as part of the Centrino Duo chipset) and also the new range
of Apple iMacs.
The Core Duo replaces the Pentium M and significantly outperforms it
at the same clock frequency. Core Solo is a scaled-down version
with only one core.
Preventative Maintenance
Cleaning
General cleaning
Caring for hardware can extend its Mean Time Between Failures
(MTBF) period considerably.
A toolkit should contain cleaning supplies. You'll certainly need a lintfree soft cloth (chamois). Outer-surfaces can be cleaned with a
simple soap-and-water solution, followed by a clear water rinse,
ensuring that none of the liquid drips into inner workings.
You can then apply an antistatic solution (spray) to prevent the buildup of static charges. To remove dust from inside cabinets, you will
find a small paintbrush is handy.
Oxidation
Corrosion or oxidation build-up on electrical contacts reduces the flow
of electricity through the connection. The easiest way to reduce
corrosion is to never touch electrical contacts with your skin —
because the moisture on your body can start corrosive action.
The oxide build-up can be gently rubbed off with a fine emery cloth, a
pencil eraser, or a special solvent-wipe. It can also be dissolved with
an electrical-contact cleaner spray. If you use the emery cloth or
eraser, always rub toward the outer edge of the board to prevent
damage to the contacts. Rubbing the edge may lift the foil from the
PCB.
Chip creep
Thermal cycling (heating and cooling, when equipment is switched on
and switched off) can cause socket-mounted devices to move slightly,
causing pin contact problems. This phenomenon, known as chip
creep, can be solved by re-seating (removing and reinstalling).
Use of alcohol-based cleaners
To clean other internal components, such as disk-drive read/write
heads, use lint-free foam swabs and isopropyl alcohol (IPA) or
methanol. However be sure to avoid using these on plastic surfaces,
which can become tarnished.
Preventive maintenance procedures
Dust
The electrical charges inside a PC attract dust particles, forming an
insulating blanket that traps heat and can cause components to
overheat.
The PC can never be dust-free because the PSU fan pulls air from
outside through the case. Another access point is uncovered
expansion-slot openings. Note that missing slot covers also disrupt
the designed airflow patterns inside the case, causing components to
overheat due to missing or inadequate airflow. It's best to keep all
slots holes covered.
Smoke also collects on all exposed surfaces. Its residue is sticky and
clings to the surfaces. Smoke residue is particularly destructive to
moving parts like floppy disks & fan motors.
Dust build-up can be taken care of with a soft brush. Special staticfree canisters of compressed gas or air can also be used to blow dust
out. A static-free vacuum can also be used. Be sure to use a staticfree vacuum because normal vacuums are, by their nature, static
generators. The static-free vacuum has special grounding.
Heat Build-up
PCs are designed to run at normal room temperatures. If the ambient
temperature rises above 85 °F, heat build-up can become a problem.
High humidity can also increase problems.
Make sure that the area around the PC is uncluttered so that air can
flow freely. It is very easy for a high-speed component to fry if its fan
fails. Check for other sources of heat such as direct sunlight or
portable heaters.
Protecting Monitors
Monitors benefit from periodic cleaning & dusting. Aerosol sprays,
solvents, and commercial cleaners should be avoided because they
can damage the screen and cabinet.
A cloth that is damp (not dripping) with soapy water is fine for
cleaning the monitor. Make sure that the monitor's power cord is
disconnected from any power source before washing. The screen
should be dried with a soft cloth after rinsing.
If a monitor is to be left on for extended periods with the same image
displayed on the screen, turn down the intensity level of the monitor
or install a screen saver program to avoid burn-in. Most modern
monitors have automatic level adjustment to protect against burn-in.
Caring for LCD Displays
LCD screens should be cleaned periodically with a glass cleaner and
a soft, lint-free cloth. Spray the cleaner on the cloth and then wipe
the screen. Never spray the cleaner directly on the screen. Also,
avoid scratching the surface of the screen. It is relatively easy to
damage the front polariser of the display. Take care to remove any
liquid droplets from the screen because they can cause permanent
staining. After cleaning, allow 30 minutes for complete drying. The
screen should be shielded from bright sunlight and heat sources.
Moving the laptop from a cool to a hot location can cause damaging
moisture to condense inside the housing (including the display). It
should also be kept away from ultraviolet light sources and extremely
cold temperatures. The liquid crystals can freeze in extremely cold
weather. A freeze / thaw cycle may damage the display and cause it
to be unusable.
Protecting Hard-Disk Drives
Rough handling is responsible for more hard-disk drive damage than
any other factor. The drive should never be moved while you can still
hear its disks spinning. The disk is most vulnerable during start-up
and shutdown, when the heads are not fully flying. If the drive must
be moved, a waiting period of one full minute should be allotted after
turning off the system.
If a hard-disk drive is to be transported or shipped, make sure to pack
it properly, in an oversized box, with antistatic foam all around the
drive. You may also pack the drive in a box-within-a-box
configuration, once again using foam as a cushion.
At no time should the hard drive's housing, which protects the
platters, be removed in open air. The drive's disks and R/W heads
are sealed in the airtight housing. The contaminants floating in
normal air will virtually ruin the drive.
Protecting Removable Media Drives
Protecting Removable Media
Magnetic tapes and floppy disks store information using magnetised
spots, so external magnetic fields will have an adverse effect on their
stored data. Never bring tape cartridges or floppies near magnetic
field–producing devices, such as CRT monitors, television sets,
power supplies or loudspeakers. They should also never be placed
on or near appliances such as refrigerators, freezers, vacuum
cleaners, and other equipment containing motors.
Proper positioning of the drive, and proper connection of peripheral
interface cables, helps to minimise noise and radio frequency
interference (RFI). Signal cables should be positioned away from
magnetic-field sources as well.
Store media in a cool, dry, clean environment, out of direct sunlight.
You should never touch the surface of the magnetic tape, floppy disk,
or CD/DVD disc — the natural oils from your skin can cause physical
damage to the floppy's coating and partially block the laser in a CDROM or DVD drive, causing it to be unreadable.
Maintaining Removable Media Drives
Cleaning the R/W heads in tape and floppy drives removes residue
and oxide build-ups from the face of the head to ensure accurate
transfer of data from the head to the disk. Likewise, cleaning CDROM and DVD drives removes contaminants and build-up from the
laser lens in the drive.
In the case of floppies and tape drives, you should manually clean the
heads with lint-free or cellular foam swab coated with IPA. Automatic
cleaning kits include abrasive disks that scrub the faces of the R/W
heads to remove build-up. These kits can eventually wear away the
R/W head and damage it and should be avoided.
On the other hand, CD-ROM/DVD drive-cleaning kits offer cleaning
discs that brush the laser lens to remove dust and other
contaminants. It is also common practice to keep discs free from
smudges and dust by wiping them gently with a soft cloth. Wipe from
the centre outwards.
Manual cleaning operations involve removing the cover of the drive,
gaining access to the R/W heads, and cleaning them manually with a
swab that has been dipped in alcohol. Together, these steps provide
an excellent preventive maintenance program that should ensure
effective, long-term operation of the drive.
Protecting Input Devices
To remove dirt and dust particles from inside a keyboard,
disassemble the keyboard and carefully brush particles away from the
board with a soft brush.
When using a trackball mouse, keep its workspace clear, dry, and
free from dust. The ball should be removed and cleaned periodically.
Use a lint-free swab to clean the X and Y rollers inside the mouse.
Removing build-up from the trackball rollers with a sharp instrument
— such as a knife — can place cuts and divots in the roller and
permanently damage the mouse.
Touchpad panels should be cleaned periodically with mild soap and
water and a soft, lint-free cloth. Rinse the residue from the pad by
wiping it with a cloth dampened in clear water. Never pour or spray
liquids directly on the computer or the touch pad. After cleaning,
allow 30 minutes for complete drying. Never use sharp or pointed
objects to tap the pad because these items may damage the surface
of the pad.
Troubleshooting
Basic troubleshooting techniques
Preparing a proper work area
You need a clear, flat workspace with an adequate number of main
sockets. In addition to usual work comforts the area should be away
from bustle and well-lit. The following will help:
A compartmentalised tray to keep track of small parts, such as screws
and connectors.
Masking tape — to label parts, where they go, and how they are
connected.
A small notepad or book to keep track of your assembly /
troubleshooting steps.
A magnifying glass to help with reading small part numbers.
Diagnostic and repair tools
Hand Tools
Your tool kit should contain a range of both flat-blade and Phillipshead screwdrivers in both jeweller's-size and medium-size. You may
want to include a small set of miniature nut drivers, a set of Torx
drivers, and a special non-conductive screwdriver-like device called
an alignment tool. You also need a couple of pairs of needle-nose
pliers and wire-cutters. When working with older PCs, IC pullers
(extractors) may be useful for removing ICs prior to reseating..
Using a Multimeter
Multimeters are available with both analogue and digital read-out and
can directly measure values of voltage (V), current in milliamps (mA)
or amps (A), andresistance, in ohms (O). They are referred to
as analogue VOMs (volt-ohm-milliammeters), or DMMs (digital
multimeters). You can also use a meter to check diodes, transistors,
capacitors, motor windings, relays & coils.
Select the proper measurement function, usually DC voltage for
testing the PSU's DC output. Make the readings between 0V
("ground") and system board power-supply connector. The DC
voltages that normally expected in a PC are +12V, +5V, +3.3V, –5V,
and –12V, varying ±5%.
First set the meter to its highest voltage range to ensure that the
voltage being measured does not damage the meter. You can then
decrease the range setting to achieve a more accurate reading.
Voltage is measured by placing the meter in parallel
with (i.e. wired across) a component, or measured
between a pin and ground. Current is measured by
placing the meter in series with (i.e. acting as part of
the wire) components.
Resistance is measured in parallel, across a
component — but that component must be
disconnected from the circuit (leaving, at most, one
circuit connection).
The second most popular test is the resistance, or continuity test,
often used to test fuses. The second most popular test is the
resistance, or continuity test, often used to test fuses. Unlike the
voltage check, resistance checks are always made with power
removed from the system.
Resistance checks also require that you electrically isolate or remove
the component being tested from the system. For some components,
this means de-soldering at one end.
If a fuse is good, the meter should read near 0 ohms. If it is bad, the
meter reads infinite. The resistance function also is useful in
checking for cables and connectors.
To check a speaker, just disconnect the speaker from the system and
connect a meter lead to each end. If the speaker is good, the meter
should read near 8 ohms. If the speaker is defective, the resistance
reading should be 0 or infinite.
Occasionally you may need to check the mains power being applied
to the PSU, usually at the end of the mains lead. This is rare in the
field because there will usually be alternative mains-powered devices
you can use to test power leads. Care must be taken with these
potentially lethal voltages.
Information Gathering
Gather information from users about the system's surroundings, any
symptoms or error codes, and the situation that existed when failure
occurred. Ask the user to list the steps that led to the malfunction.
This can help you narrow a problem down to a particular section of
the computer.
Observe the symptoms of a malfunction to verify the problem for
yourself. Remember: the user is one of the most common
sources of PC problems.Look for signs of extended use (frayed
cords, missing slot covers) for clues that problems might be caused
by usage or aging.
Power-On Self-Test (POST)
Some PCs give number codes on the display, or beep on the internal
speaker when errors occur. Conversely, other PCs display a written
description of the error. The error messages and codes will vary
among different BIOS manufacturers and from version to version. A
useful guide can be found atwww.bioscentral.com
Initial Troubleshooting Steps
Successful troubleshooting results from careful observation,
deductive reasoning, and an organised approach to solving
problems. Begin at the outside of the system and move inward.
Always try the system to see what symptoms you produce and isolate
the problem to either software or hardware. Finally, isolate the
problem to a section of hardware or software.
Performing the Visual Inspection
Check the outside of the system first. Look for loose or disconnected
cables. Consult all the front-panel lights. If no lights display, check
the power outlet, the plugs and power cords, as well as any power
switches that may affect the operation of the system. Try to localise
the problem by systematically removing peripherals.
Once inside the case, try swapping suspected devices with known
good parts from another computer of the same type. Try to restart the
system after performing each correctional step.
Check all system jumper settings to see that they are set correctly for
the actual configuration of the system. Check the CMOS setup for
enabled settings that may not be correct. Consult any user or
operations manuals for built-in self-diagnostic features. In addition, a
manual may contain probable cause and suggested remedies.
Watching the Boot-Up Procedure
1.When power is applied, the power-supply fan activates.
2.The keyboard lights flash as the rest of the system components are
being reset.
3.BIOS message displays on the monitor.
4.Memory test flickers on the monitor.
5.The floppy disk drive access light comes on briefly.
6.The hard disk drive access light comes on briefly.
7.The system beeps, indicating that it has completed its POST and
initialisation process.
8.The FDD or HDD lights illuminate as the BIOS tries to find the
bootstrap loader.
9.For Windows machines, the Starting Windows message appears
on-screen.
By knowing the sections involved in each step, you can suspect a
particular section of causing the problem if the system does not
advance past that step.
Software Diagnostics
The most common packages test the memory, processor, keyboard,
display, and the disk drive's speed. The menu's IRQ Information, I/O
Port Information, and Device Drivers options are valuable in locating
conflicts.
If a diagnostic program indicates that multiple items should be
replaced, replace the units one at a time until the system starts up.
For companies that repair or build computers, diagnostic programs
that perform continuous burn-in tests are a valuable tool. A program
runs continuous tests on the system for an extended burn-in period,
without intervention from a technician or operator.
Hardware Troubleshooting
After removing the cover, perform a careful visual inspection looking
for signs of overheating. Make a very quick check of the ICs by just
touching the tops of the chips with your finger to see whether they are
excessively hot. — i.e. hotter than usual. Check that components and
connections have not come loose, and for foreign objects. Remove
any built-up dust.
Field-Replaceable Unit Troubleshooting
Field-replaceable units (FRUs) are the portions of the system that you
can conveniently replace in the field. When exchanging system
components, be sure to replace the device being removed with one of
exactly the same type. Just because two components have the same
function does not mean that they can be substituted for each other.
Interchanging similar parts is possible in some cases and not in
others.
Always check connections after plugging them in. Look for missed
connections, bent pins, and so on. Try to avoid unnecessary strain
on the cable. Route cables away from ICs as much as possible —
some ICs, such as CPUs, can become quite hot and may eventually
damage cables. Avoid routing cables near cooling fans because they
produce high levels of EMI.
It is often helpful to just reseat (remove and reinstall) connections and
adapter cards in the expansion slots when a problem occurs.
Oxidation may build up on the computer's connection points and
cause a poor electrical contact. By reseating, the contact problem
often disappears.
The Shotgun Approach
When you have no idea what the problem is, you should test all
external devices before removing the outer cover to check internal
devices.
The basic system consists of the system unit, the keyboard, and the
display. Other devices are optional as far as the system's operation is
concerned. When a problem occurs, you should first remove the
optional items from the system. By doing so, you divide the system in
half and can determine whether the problem exists in one of the main
components or in one of the options.
The next components to exchange are the floppy drives and the
power-supply unit, in that order. The system board is the last logical
and most difficult component to exchange. Therefore, it should be the
last component in the system to be exchanged.
Fault-Finding
Common Faults
Power Supply Problems
The PSU is connected to virtually every other component — if it fails,
it can affect the whole system. Typical symptoms include:



No indicator lights; no drive action; no display. The
system is dead.
"On" light but no drive & no display. System fan may or
may not run.
The system produces a continuous beep tone.
Checking a 'Dead' System
Visually inspect, checking for unseated cards, loose cables or foreign
objects.
1. Check that the power cable is plugged into a
functioning mains outlet.
2. Check the position of the on / off switch.
3. Examine the power cord for good connection at the
rear of the unit.
4. Check the setting of the 110 / 230 switch setting on the
outside of the power supply. This should be 110V in
the US and 230V in the UK.
5. Check the mains voltage by plugging other mains
equipment into the outlet. Alternatively use an
electrician's screwdriver or a multimeter.
6. Use a multimeter to check motherboard & disk drive
connector voltages.
If the PSU is not the cause, one of the other components must be
overloading the supply. Uninstall components one-at-a-time to
identify the cause.
Remember: with the power button off, there may still be some levels
of voltages applied to the system board. Turn off all system power
before removing parts!
Common fault: A short-circuit inside a hard drive can
force the PSU into fail-safe 'off' mode. Therefore, when
testing a PSU be sure to unplug hard drive power
connectors.
Common fault: A faulty motherboard can fail to signal an
ATX supply to power-up, but a PSU MUST have some
kind of an electrical load (e.g. the motherboard) when
being tested.
Active lights and spinning fans mean that at least some portion of the
PSU is functional. There are two likely possibilities:

A portion of the supply has failed or is being
overloaded. One or more of the voltages supplied by
the PSU is missing.
A key component on the system board has failed,
preventing it from processing, even though the system
has power.

Check the supply by substitution with a known-working PSU. By
elimination, if the cause is not the PSU then something else must be
overloading the PSU.
Common fault: the CPU fan spins once or twice and then
stops. The PSU is switching on and then overloading.
Usually indicates a faulty PSU, and should be checked by
swapping-in a known-working PSU.
System Board Troubleshooting
Observe the boot up and operation. What steps lead to the failure?
Note any error messages / beep codes. Refer to the motherboard
user manual to check for hardware configuration problems. If
possible, run software diagnostics.
Configuration Checks
If the battery fails, or has been changed, the contents of the CMOS
will be lost. After replacing the battery, it is always necessary to
reconfigure the CMOS setup. (If the motherboard has been recently
removed, CMOS pins may have inadvertently been short-circuited by
anti-static measures. CMOS should always be checked after
installing a system board.)
RAM
If software diagnostics are unavailable, use logical rotation
(swapping) of the RAM modules to locate a defective RAM module.
The first is soft-memory errors are caused by infrequent and random
glitches in the operation of applications and the system. You can
clear these events just by restarting the system. Hard-memory errors
are permanent physical failures.
Mixing RAM types / speeds can cause the system to lock up and give
errors.
Processor
If the CPU is faulty the speaker may issue a slow, single beep, with
no display or other I/O operation. If the system consistently locks up
after a few minutes, this is a good indication that some heat build-up
problem is occurring.
Troubleshooting Video
If the screen flickers upon entering Windows, reboot and press F8
when the "Starting Windows" message appears, and select Safe
Mode. This should load Windows with the standard 640×480×16color VGA driver, which nearly all monitors support.
Troubleshooting Monitors
The first step in isolating the monitor as the cause of the problem is to
exchange it for a known good one. If the replacement works, the
problem must be located in the monitor. Refer the monitor to qualified
technicians.
Troubleshooting Floppy Disk Drives
Activity light stays on constantly — means the signal cable is
reversed.


FDD errors are encountered during boot up.
IBM-compatible 6xx (that is, 601) error code.
Check for foreign objects, e.g. a dust cover that may have fallen off a
disk.
Troubleshooting Hard Disk Drives



The computer does not boot up when turned on.
No motor sounds are produced by the HDD
Controller Failure, indicating a failure to communicate
with the HDD.



No Boot Record Found / Non-System Disk / Disk Error /
Invalid System Disk — boot files are not located in the
root directory.
Missing Operating System / Hard Drive Boot Failure /
Invalid Drive or Drive Specification — disk's Master Boot
Record is missing or corrupt.
An IBM-compatible 17xx error code is produced on the
monitor screen.
If the configuration information is correct and you suspect a hard disk
drive problem, the first task is to determine how extensive the
problem is.
Check the signal cable for proper connection at both ends. Exchange
the signal cable(s) for a known good one. Check the
Master/Slave/CS jumper settings. Exchange the HDD power
connector with another one from the power supply, to make certain
that it is not a source of problems.
Windows NT / 2000 / XP / Server 2003 boot failures
If the main partition is NTFS-formatted then it cannot be read using
MS-DOS or Windows 9x boot floppies. Instead, you should use a
bootable CD such as Windows PE or Bart PE, or use the Windows
2000 / XP Recovery Console. To correct the master boot record,
use FIXMBR.
http://www.bootdisk.com/ contains handy hints on how to fix boot
problems and how to create bootable CDs.
CD-ROM Drives
The steps for a CD-ROM drive are almost identical to those of an
HDD.
In addition, check for simple user problems. Is there a CD in the
drive? Is the label side of the disk facing upward? If there is a CD
locked inside, insert a straightened paper clip into the tray-release
access hole.
USB Port Checks
Check the CMOS to make sure that the USB function is enabled
there. If the USB function is enabled in BIOS, check in the Windows
Control Panel > System > Device Manager to check that the USB
controller appears there. If a USB device does not install itself
automatically, you may have conflicting drivers loaded for that device
and you may need to remove them.
Fault-finding technique
Rule 1 — Visual inspection
Carry out a visual inspection looking for obvious signs of problems:
Poorly-seated connectors or expansion cards
Loose connectors (but some connectors are meant to be loose!)
Foreign objects — for example loose screws
Physical damage
Motherboard power connector incorrectly aligned
Rule 2 — Methodical testing
Operation of the PC can be broken down into three stages:
Power
The clearest sign of a power problem is when the power supply fan
fails to spin. If the fan is spinning then main power must be available.
If the CPU fan fails to spin then there may be a fault with the power
supply's output. Check the power connector voltages with a
voltmeter.
Core system
A PC requires only three parts for basic operation: a CPU,
motherboard and RAM. We'll also need a graphics card so we can
see whether the core system is working.
If the core system fails then we should resort to testing each part
individually by swapping with similar parts in a known-working
computer.
The BIOS can produce patterns of beeps on a speaker that identify
common faults (such as no video card or memory error). These are
known as POST (Power On Self-Test) codes.
Extras
If the core system works, plug in extra components one at a time,
testing each for full functionality before continuing. It is recommended
that you test the floppy drive first: this will give you access to disk
utilities when testing hard drives. It is then recommended that you
test the hard disk drive. If you can install a working operating system
then this will allow you to test other devices such as CD-ROMs,
sound cards and network cards properly.
L1 , L2 and L3 Cache
Level 3 or L3 cache is specialized memory that works hand-in-hand with L1 and L2
cache to improve computer performance. L1, L2 and L3 cache are computer processing
unit (CPU) caches, verses other types of caches in the system such as hard disk cache.
CPU cache caters to the needs of the microprocessor by anticipating data requests so that
processing instructions are provided without delay. CPU cache is faster than random
access memory (RAM), and is designed to prevent bottlenecks in performance.
When a request is made of the system the CPU requires instructions for executing that
request. The CPU works many times faster than system RAM, so to cut down on delays,
L1 cache has bits of data at the ready that it anticipates will be needed. L1 cache is very
small, which allows it to be very fast. If the instructions aren’t present in L1 cache, the
CPU checks L2, a slightly larger pool of cache, with a little longer latency. With each
cache miss it looks to the next level of cache. L3 cache can be far larger than L1 and L2,
and even though it’s also slower, it’s still a lot faster than fetching from RAM.
Assuming the needed instructions are found in L3 cache (a cache hit), bits of data might
be evicted from L1 cache to hold the new instructions in case they’re needed again. L3
cache can then remove that line of instructions since it now resides in another cache
(referred to as exclusive cache), or it might hang on to a copy (referred to as inclusive
cache), depending on the design of the CPU.
For example, in November 2008 AMD® released their quad-core Shanghai chip.
Each core has its own L1 and L2 caches, but the cores share a common L3 cache. L3
keeps copies of requested items in case a different core makes a subsequent request.
The architecture for multi-level cache continues to evolve. L1 cache used to be external
to the CPU, built into the motherboard, but now both L1 and L2 caches are commonly
incorporated into the CPU die. L3 cache has typically been built into the motherboard,
but some CPU models are already incorporating L3 cache. The advantage of having onboard cache is that it’s faster, more efficient and less expensive than placing separate
cache on the motherboard.
Fetching instructions from cache is faster than calling upon system RAM, and a good
cache design greatly improves system performance. Cache design and strategy will be
different on various motherboards and CPUs, but all else being equal, more cache is
better.
"L1 cache is physically next to the processing core and is implemented in SRAM, or Static
RAM which is fast and constant when powered on. It does not require refresh cycles. It is
generally split with half used for instruction code and the the other used for data.L2 cache is
physically close to the core, but is implemented in DRAM or Dynamic RAM and goes through
refresh cycles many time a second
to retain its memory. It is not as fast as L1 and cannot be accessed during refresh.L3 cache
has come into vogue with the advent of multi-core CPUs. Whereas these chips will have both
L1 and L2 caches for each separate core; there is a common fairly large L3 shared by all
cores. It is usually the size of all other caches combined or a few multiples of all other caches
combined. It is also implemented in DRAM. One unusual thing is that a multi-core chip that is
running software that may not be capable of or need all cores will have a core flush its
caches into the L3 before that core goes dormant.
L1 Cache is the fastest Cache, each core has its own L1 cache its the smallest but its the
fastest and the first one to accesses by the Core.
L2 Cache is slower than L1, L2 cache is the 2nd cache that the core search's for its data, and
bigger than L1.
L3 Cache is shard between all of the cores, in the core i7 for example, is shared between all 4
cores, and bigger than both L1 and L2.
so basically what your saying is, Cpu first search's L1 cache, if a miss happens, then it goes to
the bigger cache which is L2, if it don't find the data that is looking for there,then it goes to
the bigger Cache which is L3 Which is Shared between all 4 cores.
so is L1 Cache faster because its smaller than l2 and l3 or is it faster because its the first
cache the cpu looks into?
How to Select the Best Motherboard for Your
Computing Needs
egardless of whether one is building a computer from scratch or trying to upgrade their old
one, selecting themotherboard is one of the most important decisions they will make. Not
only does the motherboard house the central processing unit (CPU), or the computer’s
"brain," but everything else on the computer connects to the motherboard in some way or
another. This makes it one of the most critical components in the computer.
Typically, motherboards and CPUs are bought and installed together. The only exception to
this would be when a motherboard has gone bad, but the CPU still works. Since the
motherboard and CPU must match, the CPU is a major part of deciding which motherboard
to buy.
There are two main CPU manufacturers: Intel and AMD. Other manufacturers that make
CPUs manufacture them to meet one of these two companies’ design criteria. Intel was the
leading CPU manufacturer for many years, with AMD following behind playing catch-up.
Today, however, these two manufacturers each create their own designs, which, while being
similar in capacity, are not identical. Nor are they replacements one for another.
There are a large number of motherboard manufacturers in the marketplace. This makes
choosing a motherboard a challenge, even for an experienced computer geek. While the
major computer manufacturers produce their own proprietary motherboards, these other
manufacturers provide their wares to individuals and smaller computer manufacturers.
Determine How Much Computer Is Needed
Ask any computer geek or sales representative which motherboard to buy, and their advice
will likely be to buy the newest, biggest, and fastest. The standard argument is that since
computers change so fast, buying anything less than the latest ensures that the computer
will be obsolete all the sooner.
While this advice is valid if one is trying to keep up with the latest technology, it may not be
valid for the average computer user. More than anything, advances in computer designs are
driven by graphics applications and 3D gaming, which are the heaviest computer power- and
memory-users. For those who use these sorts of applications, there is never enough
computer power, memory, or speed.
However, if a computer is only going to be used for surfing the Internet, sending emails, and
keeping track of family photos, the motherboard with the fastest speed and greatest
computing power is not needed. In reality, an old 386 processor will perform those functions.
Yes, a fast computer will load those pictures faster, but whether this is worth the extra cost is
something each buyer has to decide for him/herself.
While it is always best to buy a little more than what one needs in order to have expansion
room for future uses, it is easy to become carried away and buy the biggest and best.
However, the perfect computer for anyone is one that provides a little more capacity than
they will ever use, without costing more than they need to spend.
Major Selection Criteria
While there may be a host of reasons why an individual selects a particular motherboard,
there are only four major factors that one must consider. The following selection criteria
should be used to narrow down the available motherboards so that the motherboard which is
selected can be used for the intended application.
Processor
Before deciding on a motherboard, it is important to determine which type of CPU will be
used. CPUs vary in size and pin configurations. Typically, a motherboard will work for a
number of different CPUs, but not all will fit in the same motherboard. Intel and AMD, the two
major CPU manufacturers, each use different pinouts for their chips, so a motherboard that
works for one will not work for the other.
In addition, each of these manufactures uses several different socket pinouts. The socket
must match the CPU exactly for the two to be able to work together. There is no sense in
trying to provide a listing of which sockets fit which processors, as the available processors
are constantly changing; however, the most common sockets are as follows:
Manufacturer
Socket
Used For
Intel
Socket
2011
Intel’s most recent LGA socket. Used mostly by gamers
for six core i7 processors.
Intel
Socket
1366
Workstation class computer using the i7 core or the
Xenon 3XXX series. Has the pins on the motherboard.
Intel
Socket
1156
The average consumer socket for i3, i5, and i7
processors.
Intel
Socket
1155
A newer version of the socket 1156. Although it supports
everything the 1156 does, it adds additional support for
SATA III.
Intel
Socket 775
Intel’s first LGA socket. Still a very popular socket. The
first with the CPU pins on the motherboard.
Intel
Socket 771
The first Intel socket which allows for the use of dual
processors. Used only for server applications.
Manufacturer
AMD
Socket
Used For
Socket AM3 AMD’s latest consumer socket. Same as AM2+ but uses
only DDR3 memory.
AMD
Socket
AM2+
The most common AMD socket. Supports both AM2 and
AM3 processors.
AMD
Socket AM2
The oldest AMD socket in current production. Cannot
support AM3 CPUs or DDR3 memory.
AMD
Socket F
The latest server socket by AMD. The first socket by
AMD with the pins on the motherboard instead of on the
CPU.
Motherboards are usually listed with the socket type as one of the specifications. CPUs are
listed with the type of socket they require. Therefore, picking a motherboard which will work
with a particular CPU mostly consists of checking on the sockets. When in doubt, it is best to
check with the manufacturer of the motherboard in order to see which processors are
compatible with it.
Form Factor
Not all motherboards are the same physical size. The most common size is ATX; however,
the specification which created the ATX standard also provided for several alternate
configurations. All ATX motherboards will have the same general configuration, with the
major components located in the same places. While it is usually possible to mount a smaller
motherboard into a computer case, mounting a larger one may be impossible.
A second motherboard configuration standard called "BTX" was created by Intel at a later
time, in an attempt to solve airflow problems with the original ATX standard. However, this
standard never caught on. While there are some BTX motherboards on the market,
especially proprietary ones made by major computer manufacturers, they are not all that
common.
The DTX standard was created by AMD as an answer to Intel’s failed BTX standard.
Motherboard Form Factor
Size in Inches
Flex ATX
9.00 inches by 7.50 inches
Micro ATX/Embedded ATX
9.60 inches by 9.60 inches
Motherboard Form Factor
Size in Inches
Mini ATX
11.20 inches by 8.20 inches
Standard ATX
9.60 inches by 12.00 inches
Extended ATX (EATX)
12.00 inches by 13.00 inches
Workstation ATX (WATX)
14.00 inches by 16.75 inches
DTX
9.60 inches by 8.00 inches
Mini DTX
8.00 inches by 6.70 inches
ITX
8.46 inches by 7.50 inches
Mini ITX
6.70 inches by 6.70 inches
Nano ITX
4.70 inches by 4.70 inches
Pico ITX
3.90 inches by 2.80 inches
These dimensions are given only to help identify the type of motherboard currently in a
computer. These motherboard standards not only affect the size of the motherboard, but also
the configuration of the various connectors. Attempting to put an ITX motherboard into a
computer case which previously housed an ATX motherboard can cause serious problems,
as the card slots and connectors will not line up properly.
Memory Type
If one is replacing an existing motherboard and wants to reuse the existing memory modules,
it is important to verify that the memory modules will fit into the new motherboard. Most
modern computers use either DDR 2 orDDR 3 memory, with some of the older ones still
using DDR (sometimes referred to as DDR1). Most will have four memory slots, configured
in two banks of two slots. The other consideration for memory is speed. Not all motherboards
and memory modules have the same speed.
Chipset
The chipset configures the motherboard and controls how the computer’s CPU
communicates with the rest of the computer. It also controls the bus speed of the
motherboard; as such, it is vitally important. Chipsets will be rated by the speed at which they
operate. Choosing a high-speed chipset allows faster memory to be used, and generally
helps the computer run faster.
Please note that chipsets are not replaceable, but instead are a permanent part of the
motherboard.
Besides features, the chipset also controls what features the motherboard has. Things like
RAID control, surround sound, and support for USB 3 are all controlled by the chipset. The
features of a motherboard will normally be listed, rather than specific information about the
chipset.
Other Features and Options to Consider
While the four areas listed above are the major deciding factors when choosing any
motherboard, especially to eliminate a motherboard from the running, there are a number of
other features which can make the difference between one motherboard and another.
PCI Slots
The number and type of PCI extension card slots a motherboard has will affect the user’s
ability to add expansion cards. If the application for that computer requires a lot of expansion
cards, then a motherboard needs to be selected which has room for them. As a general rule
of thumb, the larger motherboard formats also have more expansion slots.
Input-Output (I/O) Connectors
Back in the early days of personal computers, most input and output functions were
performed by expansion cards. Today’s motherboards bring all of those functions on-board,
eliminating the need for buying and installing additional cards. The number and types of
connectors available can be critically important to some users and some applications. At a
minimum, a motherboard will have the following:

VGA monitor connection

USB 2.0 ports

10/100 Ethernet connection

Audio input and output connections
In addition, some motherboards may have any combination of the following:

USB 3.0 port

PS/2 mouse port

PS/2 keyboard port

Coaxial video jack

Optical port

Bluetooth transmitter

eSATA ports

Firewire port
While almost any computer peripheral will connect through a USB port, having these other
connections can reduce the number of things connected through USB. Although as many as
127 devices can be connected to a single USB host controller, it must be remembered that
the bandwidth of the bus must be shared between all those devices. Therefore, the more
devices which can be directly connected through other ports, the better.
Onboard Networking
Almost all motherboards have onboard networking. This eliminates the need to add a card
for the network connector. Some also have wireless network connectivity built-in.
Onboard Video
Almost all motherboards also have onboard video processing. This eliminates the need to
add a separate video card. However, with heavy graphics applications or multiple monitors,
or to gain speed, a separate video card is still recommended. Graphics accelerator cards are
especially useful for gaming.
SLI and Crossfire Compatibility
This is of special importance to high-end gamers or others who are using 3D graphics. SLI
and Crossfire are the methods for using multiple video cards together to increase
performance and quality. Most boards will have one or the other, although there are a few
boards which are compatible with both.
Selecting a Motherboard
Selecting a motherboard consists of following some basic steps. These steps work to
eliminate all the motherboards which are not what the user wants, leaving them with a
reasonable number of choices to review and compare when making the final decision.
1.
Choose the microprocessor CPU.
2.
Eliminate motherboards which do not support that CPU.
3.
Eliminate motherboards which do not fit the form factor of the computer case.
4.
Compare chipsets for the ones which best meets the user’s needs.
5.
Compare features to determine which is best for the specific application.
Buying Motherboards on eBay
At any given time, you can expect to find over 50,000 motherboards available for sale on
eBay. With such a vast selection to choose from, it is important to know what you want
before going shopping. A proper analysis based on the information provided in this guide will
prepare you to shop for a motherboard for your computer.
Motherboards have their own category on eBay. To find them, start from Electronics on the
main eBay navigation menu. From there, you can select Computers and Tablets.
Motherboards are located under the categoryComponents and Parts, so go there next.
Finally, select the Motherboards category. There is also a category forMotherboard and CPU
Combos. Buying a combo is a great way to avoid potential compatibility problems when
selecting a motherboard.
Within the Motherboards category, there are filters which allow you to narrow down your
search by brand, form factor, and compatible CPU brand. These help narrow down the
search to only those motherboards which will meet your particular needs.
Conclusion
Buying a motherboard, whether for building a new computer or upgrading an old one,
requires research and careful consideration. All components and especially the motherboard
and CPU must match for the motherboard to function correctly. As a general rule of thumb, it
is best to select the desired CPU, and then find a motherboard which is compatible with it.
Form factor is an important consideration, as not all motherboards will fit in all cases.
Although the Standard ATX format will fit most computer cases which are sold separately,
when buying a motherboard to replace an existing one, especially a slim-line computer, this
is a major consideration.
Finally, the features the motherboard offers should be considered carefully. While these are
not the main factor for determining whether or not a particular motherboard is a potential
candidate for purchase, they can be the tiebreaker between similar units. Input-output ports
are especially important because of the vast amount of peripherals that most people connect
to their computers.
The right motherboard choice will help ensure a high-speed computer which works well over
the long-term. However, choosing the wrong motherboard, or not choosing the right
components to go with a motherboard can turn a lightning-fast motherboard or CPU into a
slow, unreliable unit.
When in doubt about choosing motherboards and other components, it is always useful to
check manufacturers’ websites for more information and to talk to the vendor. Often, they
have information available to them which is not included in the listing.
Choosing a Motherboard
There are a wide variety of motherboards available today. When selecting a new
mobo for your homebuilt computer, many things have to be taken into consideration,
including:









Form Factor. The form factor is a set of standards that include the size and
shape of the board, the arrangement of the mounting holes, the power
interface, and the type and placement of ports and connectors. Generally, you
should choose the case to fit the mobo, not vice-versa. But if there is a case
that you simply mustuse (either because it's the one you happen to have or
because you really, really like that case), then make sure the motherboard
you choose is of a compatible form factor.
Processor support. You must select a mobo that supports the type and
speed of processor you want to use and has the correct type of socket for that
processor.
RAM support. Make sure that the motherboard you select supports
enough RAM of the type (DDR-SDRAM, DDR2-SDRAM, RDRAM, etc.) that you
want to use. Most motherboards manufactured as of this writing can support
at least 4 Gig of RAM, with DDR2 being the most popular type because of its
speed and relatively low cost. Most DDR motherboards also support dual
channelDDR, which can further improve performance. But to take advantage
of dual-channel, the RAM sticks must be installed in matched pairs, and the
mobo must support it.
Chipset. The chipset pretty much runs the show on the motherboard, and
some chipsets are better than others. The chipset cannot be replaced, so the
only way to solve problems caused by a bad chipset is to replace the mobo.
Read the reviews of other motherboards using the same chipset as the one
you are considering to see if a lot of people have reported problems with it.
SATA support. There's really very little reason not to use SATA drives these
days. They're priced comparably to EIDE drives, but deliver much higher data
transfer. But to use SATA, your motherboard must have SATA support. (Well,
you can actually install aftermarket SATA expansion cards, but why do that
on a new computer?)
Expansion Slots and Ports. How many of each type of expansion slot are
included? Will they be enough to meet your current and future needs? How
about Firewire support? And does it have enough USB slots for all the
peripherals you want to dangle off of it?
Reputation. Search the newsgroups to see if others have found the board
you are considering to be a lemon. One excellent Web resource for
motherboard research is Motherboards.org. When choosing a motherboard,
reliability is the most important factor. Replacing a failed motherboard
requires essentially disassembling the entire computer, and may also require
reinstalling the operating system and applications from scratch.
Compatibility. Most motherboards include drivers for all recent Windows
versions, but check the documentation just to be sure. If you plan to use the
board for a computer running another operating system (Linux, UNIX, BSD,
etc.) first check the with the motherboard manufacturer to see if it is
compatible, and then search the hardware newsgroups for the OS you will be
using to see how that particular board has worked out for others.
On-Board Features. Do you want integrated audio or video? If you don't
plan on using the computer for graphics, multimedia, or gaming, then you


may be able to save money by buying a motherboard with less-thanspectacular integrated audio and/or video.
RAID Support. RAID (Redundant Array of Independent Disks) is a set of
protocols for arranging multiple hard drives into "arrays" to provide fault
tolerance and/or increase the speed of data access from the hard drives.
Many motherboards have RAID controllers built-in, saving you the cost of
installing an add-on RAID controller.
Cost. Even if you are on a budget, the motherboard is not the place to cut
corners. Try a less fancy case, instead. A good motherboard is more
important than neon lights. But at the same time, the fact that one mobo
costs twice as much as another doesn't mean it is twice as good. By searching
newsgroups and reading hardware reviews, you're likely to find some
inexpensive boards that perform as well as (or even better than) boards
costing a great deal more.
Selecting Mother Board
 ntroduction
There are many steps in choosing a motherboard, and I will go through each step in the
process. However, I believe it is important to know about the motherboard types before
you can make an educated decision. In this article I shall discuss the different
motherboards for Intel which includes: Socket 771, Socket 775, Socket 1156 and Socket
1366, and the motherboards for AMD which include: Socket AM2, Socket AM2+,
Socket AM3 and Socket F. After discussing each motherboard I will explain how to
choose the best motherboard for your application.
 Intel
Socket 2011
Socket 2011 is the latest LGA type socket produced by Intel. Geared mostly towards the
enthusiast gamers and supporting the latest six core 32nm i7 processors it is definitely
among the fastest chips available. Just like its predecessor Socket 1366 the 2011 socket
supports both crossfire and sli. However, the socket 2011 has a lot of features 1366
didn’t have. Among these are USB 3.0, SATA III, PCI-E 3.0, Quad channel memory,
and a lot of other cool features. The down side to all this greatness is price. Unless your
looking to spend a good amount of money Socket 2011 is not for you. With processor
prices at a minimum of $600 and motherboards at a minimum of $260 this is definitely
not the proper hardware for someone on a budget.
Socket 1366
Socket 1366 is the workstation class produced by Intel. This socket uses the i7 core or
the Xeon 3XXX series which, like the previous Socket 775, contains the pins on the
motherboard instead of on the cpu. Almost all Socket 1366 motherboards support either
SLI or Crossfire, and all Socket 1366 motherboards use triple-channel DDR3 memory.
Socket 1156
Socket 1156 is the average consumer socket for Core i3, i5, and i7 processors. Socket
1156 will have a lot of the same features as socket 1366, however it will be more cost
effective. Socket 1156 will support the lower end i7 processors as well as the i3 and i5
processors. Socket 1156 will support only DDR3 memory, but in dual-channel
configuration instead of the triple-channel configuration of Socket 1366.
Socket 1155
Socket 1155 is the new revision of the previously released 1156 socket. Supporting
almost identically what the 1156 socket supports it also has some extra support for
SATA III and sever other small features. The biggest change between the 2 sockets is
the BIOS. Socket 1156 uses the typical BIOS while Socket 1155 uses the new UEFI bios
which supports full mouse support and allows for easy customizations for how the
system runs.
Socket 775
Socket 775 was the first LGA socket created by Intel where the cpu pins were located on
the motherboard. Socket 775 is still the most popular motherboard being purchased by
consumers due to its price and compatibility. Socket 775 motherboards support a range
of processors from single core to quad core and support both DDR2 and DDR3 memory.
Socket 775 replaced Socket 478 when it came out. You cannot use Socket 478 parts with
Socket 775.
Socket 771
Socket 771 is cpu interface which allows for the use of dual processors. LGA 771 was
the first server motherboards to carry pins on the motherboard instead of the cpu. Socket
771 is strictly meant for server applications. Socket 771 motherboards support DDR2
FBDIMM’s.
 AMD
Socket AM3
Socket AM3 is AMD’s latest socket for consumer use. Socket AM3 mother boards have
the similar basic socket as an AM2+ board; however AM3 boards only support DDR3
memory. Therefore an AM2 or AM2+ processor will not work in an AM3 board.
Socket AM2+
Socket AM2+ motherboards are probably the most commonly chosen AMD
motherboards. This is because Socket AM2+ motherboards support both AM2 and AM3
processors and allow you to mix an AM3 processor with DDR2 memory whereas when
you use an AM3 board it only supports DDR3.
Socket AM2
Socket AM2 is the oldest socket i am going to discuss in this article. Socket AM2 boards
can not support the AM3 processor and only support DDR2. Socket AM2 boards were
replaced with the Socket AM2+ motherboards.
Socket F
Socket F is the latest server socket by AMD. It uses the LGA design with the pins on the
motherboard instead of on the processor. It is the first socket to be created by AMD with
this technology. Socket F allows for the dual processor setup and uses DDR2 memory.
 Choosing a Motherboard
1.
Motherboard Compatibility
ProcessorWhen choosing a motherboard one of the major things you need to consider is the
processor which you’re going to use. Whether it is AMD or Intel and what socket
you’re going to be using as explained above. The second thing you need to look at with
the processors is to see if the core size (45nm or 65nm) is supported along with the front
side bus, Hyper Transport, or QPI depending on which the processor has. To understand
processors better please visit How to choose a CPU.
MemoryChoosing the proper memory for your motherboard is extremely important. If you
choose the wrong memory the computer won’t work at all. The first thing you need to
see is whether the computer supports DDR, DDR2 or DDR3. DDR2 and DDR3 are the
standard for memory right now but could change soon in the future. The second thing
that has to be looked at is the memory speed which can easily be found by looking for a
measurement in MHz or megahertz.
Form FactorChoosing the form factor for your motherboard is extremely important because in order
to choose a proper case you have to determine your motherboard size. If you have
already chosen a case, make sure to identify which motherboard form factors the case
will support, such as EATX, ATX, Micro ATX, or ITX. Motherboard form factor is
also important - the larger the motherboard, the more options that motherboard will
have. For example, a Micro ATX board may only have 1 PCI-E and 2 PCI slots while
an ATX board may have 2-3 PCI-E slots, 3 PCI slots, and 2 PCI-E x1 slots. EATX is a
2.
motherboard form factor that is only found in servers and workstations, and is not for
use in a typical consumer desktop system.
Motherboard Features
Onboard VideoThis option is important for the individuals who are not going to install separate video
cards in their system. Onboard video is not meant for gaming of any sort and is best
suited to the people who browse the internet or watch videos.
Onboard NICThis is a good option for every one due to the fact a separate network card is no longer
needed. This frees up room in the machine allowing for better airflow and at the same
time allows for more slots for video cards or other necessary expansion cards. When
looking at motherboards onboard NIC is always a good option.
Onboard USBAll motherboards have onboard USB. The only difference is the number of USB each
board has. The only way to determine the right number for you is to decide how many
USB items you will connect to your computer. Always make sure to have a few more
USB then necessary to make sure you have room for adding something in the future.
SLI & Crossfire CompatibilityThis option is most important to high end gamers or 3d graphics engineers. SLI and
Crossfire is the method of using multiple video cards together to increase performance
and quality. Most boards you will see that carry these attributes are either Crossfire or
SLI. However, there are a few boards which allow the compatibility for both SLI and
Crossfire since the release of the LGA 1366 motherboards.