Water cooling: AIO and custom loop

In short: Liquid cooling carries heat from the processor or graphics card through tubes to a radiator, where fans release it to the air.

In more detail: Liquid absorbs heat better than air. A pump moves coolant through a cooling block on the processor, then to a radiator, which releases the heat via fins and fans. For powerful processors this is efficient and can be quieter than large air coolers.

In Depth

AIO (all-in-one)

A closed, pre-assembled compact liquid cooler: pump and block, tubes and radiator (120, 240, 280, 360 mm) are filled and sealed at the factory. Installation similar to an air cooler, low maintenance but not expandable. The pump is a wear part; lifespan is usually five to seven years. The radiator is mounted at the top or front, the pump if possible lower than the radiator so that no air collects.

Custom loop

A self-assembled circuit of cooling blocks (CPU, GPU, motherboard), pump, reservoir, radiators, tubes or hoses and fittings. It is very powerful, visually impressive and expandable but expensive, laborious and must be maintained (change coolant, check for leaks). It usually pays off only for enthusiasts or with very powerful hardware.

Advantages and disadvantages compared with air

Advantages: lower temperatures under high load, space around the processor, heat is channelled out of the case. Disadvantages: higher price, pump noise, more parts that can fail, and the (small) risk of leaks. Good air coolers are similarly capable for mid-range processors, very reliable and silent when failing.

Notes

Motherboard and case must accommodate the radiator (check dimensions). The pump ideally runs at constant or regulated speed, the fans by liquid temperature. For custom loops use suitable coolants and do not mix metals (copper and aluminium) because of corrosion. Check tightness of new loops before switching on the system.

See also: Case ventilation and airflow, Cooling and thermal paste, Overclocking