Once upon a time computer cooling was not very important. Back in those days computers were slow and had few components, producing little heat. With over 100,000,000 transistors crammed into a space smaller than a fingernail, a modern processor consumes over 80 watts of electricity alone. Without proper cooling, a processor will melt itself down in a matter of seconds.

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This is a basic overview of the various methods used to cool a processor and the other parts of a computer. It will provide a basic understanding of the methods used, weighing each against the other. This is not a how-to; it is intended to introduce the subject information on the available options.

Cooling Methods

There are four basic methods:

Passive Air cooling
Active Air cooling
Water Cooling
Refrigeration

Each of these methods has various advantages in performance, cost, space, noise, reliability, and ease of instillation. Most modern computers are equipped by the manufacturers with a combination of passive and active air cooling from the factory.

Passive Air Cooling

Passive air cooling relies on stagnant air to dissipate generated heat. Every electrical component in existence generates some heat, but most of the time the casing of the component itself dissipates the heat adequately. Heatsinks (a piece of thermally conductive metal, designed to increase surface area exposed to air) are used when the casing is not enough. Dust or any foreign matter that builds up on these surfaces acts as an insulator, trapping the heat. This will eventually lead to component failure. Another big factor in passive cooling is the ambient temperature (room temperature); nothing short of refrigeration will allow you to make something colder than the air itself.

Pros: Silent, cheap (mostly)

Cons: The worst possible form of cooling, severely limited by ambient air temperature, dust buildup greatly effects cooling performance

Chipset Heatsinks

Chipset Heatsinks

Active Air Cooling

This is the most common form of computer cooling, consisting of a heat sink and a fan to move air across the heat sink. Virtually every modern computer has this form of cooling in it somewhere. It is a very cost-effective and efficient method of cooling. Unfortunately, modern computers generate so much heat that larger and faster fans are required to increase the airflow over the heatsinks. Computer noise levels are approaching that of a jet airplane ready for takeoff. Also, without some sort of software and/or hardware overheat protection, a fan failure would result in meltdown even with a computer running idle. Although active cooling is much better than passive cooling, it is still limited by room temperature. The last side-effect fans have is dust. They tend to suck dust in (much like the vacuum cleaner they sometimes sound like), and it eventually starts filling the corners and sticking to stuff. Dust filters can be purchased for this problem, but they will need cleaned on a regular basis, and are usually somewhat inconvenient to get to.

Note: If you are rather annoyed with the fan noise coming from your computer you can do something about it without resorting to a different cooling method. There are tons of different fans available for you to buy, and the factory fans are usually far from the best. Fans are rated by CFM and DB (how much air they ‘push’ and noise produced). They are all quite cheap and install fairly easily.

Pros: The most cost-effective way to cool

Cons: Can be rather noisy, limited by ambient air temperature, more dust buildup due to fans sucking it in

A CPU Heatsink/Fan and several 80mm case fans

Water Cooling

Most people have not heard of water-cooling a computer before but water has been used to cool for 1000’s of years. It is essentially the same type of cooling that a car uses. There is a water pump (to circulate the water), a water block (a heatsink designed for water cooling), a radiator (a heatsink designed to cool the water itself), and some sort of a reservoir to store the water in. Water flows through the water block, cooling whatever component it is attached to (heating the water), and out to the radiator, where the water itself is cooled. A few fans are still necessary for the radiator, but these can be larger, slower fans, not the loud small high-speed fans normally used. Water cooling is very effective; resulting is lower temperatures than either passive or active cooling. Temperatures are also much more stable with water cooling, slow increases and decreases, due to the thermal mass of the water itself. Naturally, water cooling systems for computers cost a bit more than active air-cooled systems, but they are still within reasonable ranges. It is possible buy parts separately, in kits, or even buy special cases with all the equipment already built-in. Installing such a system is a little complicated, but not out of the range of anyone who can install most computer hardware. Attention to detail and following directions makes the job feasible. Again, without protective software/hardware, a malfunction will convert a computer into an expensive doorstop.

Pros: Very effective cooling, very stable temperatures achieved, reduced noise

Cons: Costs more, possible hazard to computer components, takes up considerable space, hard to install correctly

(3 Water Blocks)

(a radiator)

(and a all-in-one water cooling kit)

Homemade water cooling gone mad!

Refrigeration

Cooling a computer by means of refrigeration is generally done by using pielters combined with water cooling. This is an extreme method of cooling, and is never done by average, or even most advanced computer users. For those wishing to send their computer out on a rover to explore Venus, or want to overclock to the max, you might try this. The one and only advantage to this form of cooling is the very low temperatures achieved can significantly improve system stability, something not normally necessary unless you overclock. A pielter is a refrigeration device that works by applying a current (electricity) across two different kinds of metal. A ‘cold’ side and a ‘hot’ side is formed on the pielter. The cold side faces the processor (or whatever needs to be cooled), and a water block is attached to the hot side to cool the pielter itself. Pielters can cool by as much as 50 degrees C below room temperature, at the cost of quite a bit of current. While this is great for cooling, there are some serious side effects. Much like a cold can of pop, pielters condensate. As water and motherboards don’t mix well, the entire motherboard must be water-proofed, and the processor must be insulated against moisture. This process will void all your warranties, and even then there is considerable risk for failure. Refrigerating a computer in this manner will cost you some money (at least $250). Installing such a system is a lot of work, risky even to those with experience with this, and there are no kits or instructions, you’re on your own.

Pros: Extreme cooling, significant computer performance boost possible, fairly quiet

Cons: This will take a chunk out of your pocketbook, voids warranties due to necessary modification of computer parts, consumes lots of electricity, great hazard to computer components due to condensation, extremely difficult to install with success.

A variety of Pielters

Some of the nessary CPU insulation

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