Overclocking and Cooling
Damian Kardański
1
Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
2
Introduction
Overclocking - the process of running a computer
component at a higher clock rate (more clock cycles
per second) than it was designed for or was specified
by the manufacturer
As clock frequencies in digital circuits increase, the
heat generated by components running at the clock
speed also increases.
Cooling - the process of removing heat from computer
components.
3
Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
4
Quartz crystals in controling a system’s speed
Quartz crystal is silicon dioxide (SiO2) in crystalline
form. Hard, transparent material, brittle, but with
a little bit of elasticity
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Quartz crystals in controling a system’s speed
Piezoelectricity:
Ability of some materials to generate a voltage when
subjected to mechanical stress and to generate
mechanical stress when subjected to a voltage.
Piezoelectricity was first discovered by Pierre and
Jacques Curie in 1880 and it’s the essential feature of
quartz that makes it useful in electronic circuits.
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Quartz crystals in controling a system’s speed
The speed of a computer system is derived from
the main motherboard crystal (always 14.31818 MHz)
in conjuction with a frequency timing generator (FTG)
or a frequency synthesizer.
Frequency synthesizer chips use phased locked loop
(PLL) cicrcuity to generate synchronized processor, PCI,
AGP, and other bus timing signal that are all derived
from a single 14.31818 crystal.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
8
Beginning’s of overclocking
IBM PC AT (Advanced Technology) from 1984.
To run the system a socketed crystal of 12 MHz or 16
MHz was used. The timer chip divided the crystal
speed by 2 (speeds of 6 MHz and 8MHz). An 18 MHz
or 20 MHz crystal could be purchased for $1.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
10
Overclocking modern PCs
Most modern motherboards allow to change speed,
timing and voltage settings of computer components
in the BIOS Setup.
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Overclocking modern PCs
Processors run at a multiple of the processor bus
(FSB/CPU bus/PSB) speed and the selected multiple is
locked within the processor.
Example:
Intel Pentium 4 3.2E processor running at 3200 MHZ
on 800 MHz CPU bus (locked multiplier – 4).
Increasing CPU bus speed to 832 MHz (4%) results
in the increase of the processor speed to 3328 MHZ.
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Overclocking modern PCs
Increasing FSB’s speed increases the speed of other
buses (memory, PCI, AGP) by the same percentage.
Therefore, after increasing FSB’s speed, if the memory
or any other component is unstable at the higher
speed, the system will still crash, even though the
processor might have been capable of sustaining it.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
14
Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
15
Heatsinks - passive
Heatsink – an object that absorbs and dissipates heat
from another object using thermal contact.
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Heatsinks - passive
Heatsinks are rated for their cooling performance.
Typically, the ratings are expressed as a thermal
resistance in degrees centigrade per watt (°C/W),
where lower is better.
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Heatsinks - active
Active heatsinks incorporate fans or other electric
cooling device that requires power to run. This
provides constant and more efficient air flow.
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Heatsinks – Thermal interface materials
To have the best possible transfer of the heat from the
device to the heatsink some type of thermal interface
material is placed between those two. It’s typically a
ceramic, alumina or silver-based grease but it can also
be in the form of a special pad or even a type of
double-stick tape.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
20
Liquid cooling - Heatpipes
Heatpipe is a heat transfer device able to transport
considerable amount of heat energy between two
interfaces.
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Liquid cooling - Heatpipes
Heatpipe - hermetically sealed tube with a fine wick
structure lining the inner walls, hollow core in the
center. Vacum inside, partialy filled with a special fluid.
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Liquid cooling - Heatpipes
Heatpipe - hermetically sealed tube with a fine wick
structure lining the inner walls, hollow core in the
center. Vacum inside, partialy filled with a special fluid.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
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Liquid cooling – Water cooling
Water cooling – circulating water over the processor
or other components, therby keeping them cool. It’s
one of the most efficient types of cooling, but
expensive and very troublesome to use and maintain.
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
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Thermally advantaged chassis
Thermally advantaged chassis improve cooling for the
processor by maintaining a temperature of 38°C or
less at the processor heatsink inlet.
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Thermally advantaged chassis
To meet the requirements of the therm. ad. chassis,
the following specifications are recommended:
• Accepts an industry-standard ATX, MicroATX or
FlexATX motherboard
• Accepts an industry-standard ATX, SFX or TFX power
supply with integral exhaust fan
• Uses a removable side cover with an adjustable
processor duct and adapter card vent
• Provides a primary chassis rear exhaust fan of 92mm
or larger and an optional front-mounted 80mm fan
(excluding any fans in the power supply).
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Framework
1.
2.
3.
4.
5.
Introduction
Quartz crystals in controlling a system’s speed
Beginnings of overclocking
Overclocking modern PCs
Cooling methods
 Heatsinsks
o Passive
o Active
o Thermal interface materials
 Liquid cooling
o Heatpipes
o Water cooling
 Thermally advantaged chassis
 Processor duct
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Processor duct
Processor duct – a tube positioned directly over the
processor heatsink, allowing it to pull cool air from
outside the chassis. The Processor duct is the most
important part of the thermally advantaged chassis
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Processor duct
Processor duct’s effects can be viewed in the table.
Tests where performed in a 25° C room and the
following components were used:
-3GHz Pentium 4
-D865PERL motherboard
-GeForce 4 video card
-DDR400 memory
-Hard drive
-CD-ROM drive
-Sound card
-Rear and front fan
Without
CPU Duct
With CPU
Duct
CPU inlet
temp.
35° C
28° C
CPU fan
speed
4050 rpm
2810 rpm
Sound level
39.8 Dba
29.9 Dba
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Conclusion
Upgrading a computer system to run faster is usually
called overclocking. When chips run faster, they run
hotter, so cooling upgrades go hand-in-hand with
overclocking.
Systems that run cool tend to be more stable and
more reliable, so even if you don’t overclock your
system, ensuring that it runs cool is essential for
trouble-free operation.
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