Liquid cooling of computers is currently something reserved for hardcore users or supercomputing. However, it is quickly becoming something that is essential for normal operation, given the rising heat output of the new processors. Once upon a time processors did not require heat sinks, let alone fans, for cooling. The earlier microprocessors contained few transistors in a large area so heat was not an issue. That began to change around the time of the introduction of the 386 and 486 processors. The computer engineers were continually coming up with better manufacturing processes that increased the number of transistors that could be fit into a given area. Eventually fans were required to dissipate the heat and now the practicality of air cooling is soon to reach its limit. Many computer users are beginning to abandon air cooling in favor of liquid cooling. Manufacturers of computer cases are coming up with easy-to-setup systems and other companies are developing add-in liquid cooling kits that can be set up in standard cases.
A basic liquid cooling setup consists of a radiator, pump, reservoir, and cooling block, as well as piping between these components and a coolant. There are also variations and simplifications of these components, such as immersible pumps contained in reservoirs and so forth. Many systems also require fans to circulate air through the radiator in order to increase cooling efficiency.
The coolant can be anything from water to a specially designed coolant chemical. The reservoir holds the excess coolant and the pump is used to extract the coolant from the reservoir and circulate it through the rest of the cooling system. The cooling block is generally a hollow block of conductive metal with connections for piping, although some also consist of a hollow plastic container with a metal attachment. The radiator is a hollow metal block with passageways and has a very large surface area that allows the surrounding air or other medium to absorb heat rapidly from the coolant.
Liquid cooling is usually about 10 times more efficient at cooling a given computer system than a standard fan setup. The lowest temperature attainable is still room temperature since no compression is occurring, therefore the processor temperature usually hovers anywhere between 10-30 degrees Fahrenheit above room temperature, depending on usage and the efficiency of the cooling setup. Overclockers of processors commonly use liquid cooling to increase the headroom they have available for increasing the processor's speed without compromising stability. Those looking for more advanced cooling setups may prefer a more expensive refrigeration setup.