Date:
Thursday , November 01, 2007
Author:
Marc Adams
Editor:
Kyle Bennett
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Mega-Heatsink Roundup - 0407

Big bucks for big units! We pull out the stops and put 10 big bad cooling systems and heatsinks to the test. What coolers deliver you the best temperature drop for your hard earned dollar? We spell it out for you on a unit by unit basis.

Introduction

Anyone over the age of 21 may remember a time of "true" silent computing. I say 'true' because the only need for a fan near a computer in those days was on a hot Summer day to keep you cool. CPU's would rely on nothing more than a chunk of metal to remain cool. Boy how things have changed. With the ever increasing power requirements of computers and the desire to keep them quiet, heatsink manufacturers have designed some of the most amazing cooling products ever seen. From larger fans and the inclusion of heatpipes to using water and phase change cooling, it seems there is no limit to the lengths some of us will go to for peace of mind or just that massive overclock. You can go down to the local computer shop or swing by some website to grab some aftermarket cooler but how do you know you're getting your money's worth. Do you really want to hand over your hard earned dough because the advertising says this is the best around? How do you know those fifty seven heat-pipes will do the trick or that this nine pound chunk of metal is any good? Well, I have the answer for you and it is a lot less expensive and more fun then wasting a benjamin on marketing hype. We are about to find out if today's most popular coolers on the market deserve their popularity or should be exposed as frauds. So sit back, relax and let's cut through all the jazz and glitter and get down to the nitty gritty.

 

Thermodynamics made simple

Chances are if you're reading this you already know that without a heatsink of some sort a modern day CPU would fry itself within less than a second. Thankfully safeguards are in place in modern PC's to shut down a computer or prevent it from turning on if a heatsink is not installed or the CPU is overheating. But do you know why heatsinks work and why some are made of aluminum, copper, with heatpipes and without? This is all thanks to a little law called the Second law of Thermodynamics. Simply put, over time differences in temperature, pressure, and density tend to even out in a physical system. Basically, heat transfer always occurs from a hot body to a cold one. In our case the hot body is the CPU and the cold body (hopefully) is the heatsink.

There are three methods for heat transfer and they are conduction, convection and radiation. Only the first two are used in computers so we will ignore the last one for now.

Conduction

Conduction is the exchange of heat (energy) between two materials. i.e. A warm hand touches a cool arm and they exchange energy.

In the above picture we see a common method for conduction. The aluminum heatsink conducts heat away from the CPU and as air passes over the block it picks up some heat allowing it to cool off. This method relies heavily on good airflow across the heatsink or else the heat will remain in the metal and build up rapidly.

Convection

Convection is transferring heat to a surrounding gas or liquid, such as air or water. i.e. Boiling water on the stove transfers heat from the pot to the water. (There is also "forced convection" which uses fan or pump to move the gas or liquid away and introduce cool gas or liquid.)

Here we see forced convection at work. In this setup the aluminum block conducts heat away from the CPU as the fan forces air over the heatsink to remove the heat allowing it to cool off and the cycle repeats itself.

Now that we have learned the principles on which modern heatsinks work, let's meet today’s competitors.