Chapter 6: Understanding and
Assessing your Hardware
• Is now a good time to buy a new computer?
– There never seems to be a good time to buy; the
prices keep going down and the tech keeps
becoming more advanced.
• Moore’s Law describes the pace at which
CPUs (Central Processing Units) improve.
Named after Gordon Moore the cofounder of
Intel, this rule predicts that the number of
transistors inside a CPU will increase so fast
that CPU capacity will double every 18
months.
• For perspective if you put 10 cents in that kind
of savings account in 1965, you would have a
balance of more than $100 million today.
Moore also predicts that around the year
2020 CPU chips will be manufactured in a
different way, thus changing or eliminating the
effects of Moore’s Law.
• Evaluating your CPU : There are several types of
processors on the market: Intel processors include
the core i7, i5, i3, and the Centrino line.
• AMD processors offer the Athlon and Phenom
processors. The MS Xbox uses a custom PowerPCbased CPU with an AMD Xenon processor to perform
115 billion calculations per second.
How does a CPU work?
– The CPU is comprised of two units: the
control unit and the arithmetic logic unit
(ALU).
• The control unit coordinates the activities of all
the other computer components
• The ALU is responsible for performing all the
arithmetic calculations: addition, subtraction,
multiplication, and division. The ALU also
makes login and comparison decisions such as
determining if one unit is greater than or less
than another.
– Every time the CPU performs a program
instruction, it goes through the same series
of steps.
• It fetches the required piece of data from RAM
• It decodes the instruction into something the
Computer can understand
• It executes the instruction
This process is called a machine cycle
What makes one CPU different from
another?
• The number of cores is one distinction. A core is a
complete processing section from a CPU embedded
into on physical chip. Another distinction is how
quickly the processor can work or its clock speed. The
last distinction is the amount of immediate access
memory the CPU has called its cache memory.
How will multiple cores help?
• The quick answer is that having multiple cores
allows the CPU to process more than one
instruction at a time. This began quite a while
ago as Hyperthreading, a sped up process of
computing where the processor actually
enables a new set of instructions to start
executing before the previous has finished (this
is still a sharing of resources of a single chip
which is different from having separate cores).
• The most recent innovations in this area
includes hyperthreading techniques with
multiple cores. One of the benefits of these
CPUs is that programs that always run in the
background are now allocated a whole core so
they do not cause lag in the running of other
programs.
• The Intel i7-980x has six cores, each one
using hyperthreading, so it simulates
having 12 processors!
How do I pick the fastest processor?
– Clock speed is important along with the amount of
cache memory, and the speed of the front side
bus (FSB).
• Cache memory is a form of RAM that is
more accessible to the CPU than regular
RAM. There are several levels of cache
memory. These levels are defined by a
chip’s proximity to the CPU.
–Level 1 cache is a block of memory that is
built onto the CPU chip for the storage of
data or commands that have just been used.
–Level 2 cache is located on the CPU chip but
is slightly farther away from the CPU, or it’s
on a separate chip next to the CPU.
–Level 3 cache is farther away but bigger in
size.
• Front Side Bus (FSB) connects the processor to
the system memory. Think of the FSB as the
highway on which data travels between the
CPU and RAM. Consequently, the faster the
FSB is, the faster you can get data to your
processor—speeding up the whole process.
FSB is measured in MHz.
Modern processors are defined by the combination of
processor speed, FSB and the amount of cache.
Desktop
Processors
i3-530
i5-750
i7-980x
Notebook
Processors
Celeron 585
i5 mobile 520
i7 mobile 820
Number
of Cores
2
4
6
Max Clock
speed
2.93 GHz
2.66 GHz
3.30 GHz
Max FSB
1333 MHz
1333 MHz
1600 MHz
Max L3
Cache
4 MB
8 MB
12 MB
1
2
4
2.16 GHz
1.07 GHz
1.73 GHz
666 MHz
1066 MHz
1333 MHz
1 MB
3 MB
8 MB
– What does my computer currently have?
• Go to system properties to see. You may have
to check with the manufacturer about the FSB
and the amount of cache.
• CPU usage
– To view your current PCs usage you can open task
manager (ctrl-alt-del) and then select the usage
tab. You will see a line graph of usage over the
past several seconds. A good indicator that it may
be time for a new computer is that the usage stays
over 90% for extended periods of time.
• Evaluating RAM
– Random Access Memory (RAM) is your
computer’s temporary storage space. RAM is an
example of volatile storage meaning the data
stored in RAM will get cleared out when the PC is
turned off. (ROM or Read Only Memory is an
example of nonvolatile memory because it is
permanent).
– Why not just use the hard drive for storage?
• It is true that the storage space per dollar
makes the hard drive a cheaper alternative, but
not a logical one. It is about one million times
faster for the CPU to retrieve a piece of data
from RAM than from the hard drive. The time
RAM uses is measured in nanoseconds
(billionths of a second). But the time for hard
drives is measured in milliseconds (thousandths
of a second). It takes the Hard drive about 10
milliseconds to retrieve a piece of data.
– Are there different types of RAM?
• Yes. Currently most systems use a form of double data
rate 2 (DDR2). Double Data Rate 3 (DDR3) has an even
faster transfer rate is seen in high performance
systems.
• Older versions of RAM include: Dynamic RAM (DRAM),
static RAM (SRAM) and synchronous DRAM (SDRAM).
• RAM comes in the form of a memory module (or chip).
Most memory modules today are in the form of dual
inline memory modules (DIMMS).
• The amount of RAM that is actually sitting on memory
modules in your computer is your computer’s physical
memory.
– Windows 7 uses a memory-management
technique known as SuperFetch.
SuperFetch monitors which applications you
use the most and preloads them into your
system memory so that they’ll be ready to
go.
– Kernel memory is the memory that your
operating system uses.
• Every computer has a maximum limit on the
amount of RAM that it can support. The
mother board has a specific number of slots
into which the memory card fit, and each lot
has a limit on how much RAM it can hold. To
determine your system’s limits you can
consult your owner’s manual or go to certain
commercial websites that can determine
your systems’ RAM and it’s limits