Hardware Hacking Projects for Geeks

55

4

4. How to Build a PC

Water-Cooling System

Cost

Time

Difficulty

$50–75

a weekend

moderate

Over the last few years, it has become a popular hobby to run your PC’s

CPU at a rate faster than the factory default rate. This practice is known as

overclocking.

The Pentium or AMD processor inside your PC runs its software based on

an internal heartbeat known as the clock. The clock speed determines how

fast your system operates. AMD and Intel shamelessly flog their products

(for example, the Pentium 4 2GHz and the AMD K6II-400) based on this

clock number. Many processors that have a similar megahertz rating are

actually the same part with a different clock, potentially reducing your abil-

ity to overclock that particular processor.

Running the clock faster than what the CPU manufacturers recommend

has certain side effects. One such effect is that the CPU gets hotter than it

should. Many recently manufactured CPUs with clock speeds over 1GHz

have a temperature sensor and circuit built in, which allows the CPU to

monitor its temperature and slow things down if it gets too hot.

Many of the overclocking “pioneers” used big fans and metal-finned heat

sinks to transfer the heat generated by the faster clock rates away from the

CPU. These fans moved the air past the heat sink where a heat exchange

took place. The fans were usually noisy, and the heat sink provided only

limited cooling to the CPU. (The CPU in your PC probably has a heat sink

built in already.)

Credits

Photographs and portions of the text copyright

© 2003 Rob Dickenson.

What You Need

• A home PC with an AMD or Intel

CPU

• 1mm thick sheet of copper

• Fish tank pump

• Vinyl tubing

• Rubber bands

• Other items listed in

Exhibit A

ch04_cooler.indd 55

1/21/2002 12:26:12 PM