In addition to standard operation, any number of factors can cause heat buildup in a computer. Buildup of dust can insulate the components of a computer. Poor orientation of fans can reduce their effectiveness (in air cooled PCs). Overclocking a processor- where you remove the 'limitations' placed by the software developers on how fast the processor can go. Finally, general poor design can increase the heat generation.
There's a lot of ways you can prevent your computer from going 'boom' as a result of all of these factors.
This is probably the most common, most power intensive, and-at least in my opinion- often the least efficient method of cooling a PC. One to several fans are installed in the motherboard, and these fans are used as a sort of 'exhaust vent' system. They move the hot air out of the PC, and bring cooler air in. It's not that this isn't a good means of cooling a system. I mean, if it didn't work, it wouldn't be integrated into almost every laptop and PC on the market, would it?
The thing is, though, is that air cooling simply isn't as effective as the other methods on this list. Not only does it increase the power draw of the system, but there's also a certain limit to how much it can do. After all, a fan can only move so much air, if you're overclocking your system through the roof, the fans might not necessarily be able to keep up.
Granted, there's several different types and sizes of fans you can get- some of them are actually quite powerful. Plus, air cooling does help prevent dust buildup on your computer's inner components.
Another method of cooling the computer is to use a heatsink- a piece of metal that absorbs a lot of the heat generated by the PC. There are three different 'types' of heatsinks. Passive heatsinks involve simply clamping the piece of metal onto the components to be cooled and calling it a day. The problem with this one is dust buildup. Since it acts as an insulator, the effectiveness of the cooling system is gradually reduced.
An active heatsink adds a fan to the mix, constantly blowing over the metal. This accomplishes two things: first, it helps to prevent dust buildup on the heatsink. Second, it reduces the overall temperature, therefore increasing the amount of heat the cooling system's able to dissipate before reaching its limit. \
Finally, there's a nifty little innovation known as thermoelectric cooling.This involves using the Peltier effect in a cooling system. Basically, the Peltier effect stipulates that if there are two different metals between which heat is flowing, and the second metal has a lower capacity for heat absorption from the first, the heat will have to dissipate before reaching the second. Thus, the side that absorbs the heat becomes hot, the side that releases it becomes cold.
The lack of moving parts makes this a pretty nifty means of cooling a system, but as systems generate more and more heat, it gets harder and harder to find a thermoelectric cooling system that will work- or at least one that doesn't break the bank.
We're starting to move towards the higher end stuff. Liquid Cooling involves a series of tubes, a water pump, and a radiator. The water in these tubes absorbs heat from the computer components, is carried to the radiator, and dissipates that heat. Rinse and repeat. It's quiet, it's efficient, and it's probably one of the most popular cooling methods. Plus, unlike some of the other methods, the liquid cooling pipes can run through the whole computer, whereas with heat sinks and fans, you can usually only focus on the one or two components that generate the most heat.
A lot of gaming PCs- I'd say the majority of them- utilize this method of cooling. It works. Just make sure the pipes don't break.
Now we're talking. Liquid submersion is exactly what it sounds like. Basically, you take the computer's The Reactor X Desktopmotherboard, and dunk it in a liquid that doesn't conduct electricity, such as mineral oil. And then...well, you're pretty much done. It keeps the computer cool, it doesn't make noise, and there's no risk of a pipe breaking and your computer short circuiting as a result. I've a friend whose hobby is building PCs, and he swears by this method.
Another advantage is that this one doesn't have to be cleaned very often, unlike some of the other components. Dust buildup's an issue with a lot of desktops and cooling systems, but liquid submersion...kinda circumvents that a bit.
You may need to insulate or otherwise shield some components of the computer, depending what liquid you're using; and if the liquid isn't sealed in, evaporation could be a concern. Other than that, though, this one's pretty nice.
Phase Change Cooling
OCZ's CryoZ phase change coolerThis one's for those of you with deep deep pockets. Phase change cooling keeps your computer cool in the same way that a fridge keeps your food and drink cool. It involves compressing a gas so it turns into a liquid and then evaporating it into a gas again. The evaporation absorbs a massive quantity of heat, then the gas is moved through the system to be compressed into a liquid again.
So, yeah. If any of you were wondering how a refrigerator basically works, that's it. You can imagine that the components for phase change cooling tend to be more expensive, and use a lot more power than most of the other methods here. And truthfully, unless you're building a several thousand dollar rig that you're planning on overclocking on a regular basis, this probably isn't worth it.
Of course, you could just do what I do- live somewhere cold and leave your windows open in the winter. That works too. Kind of.