Editing Computer cooling (section)

===Heat-sinks===
{{Main|Heat sink}}
{{multiple image
 | total_width = 370
 | image1      = Harumphy.dg965.heatsink.jpg
 | caption1    = Passive heatsink on a chipset
 | image2      = Heatsink with heat pipes.jpg
 | caption2    = Active heatsink with a fan and [[heat pipe]]s
 }}
A component may be fitted in good thermal contact with a heatsink, a passive device with large thermal capacity and with a large surface area relative to its volume. Heatsinks are usually made of a metal with high [[thermal conductivity]] such as aluminium or copper,<ref>The thermal conductivity and thermal capacity of silver is better than that of copper, which is better than that of aluminium (see [[List of thermal conductivities]]). Consequently on purely technical grounds, solid silver (silver-plating is pointless) is better than copper, which is better than aluminium, for heatsinks and also for saucepans. Cost, of course, rules out silver, although enthusiasts have used silver heatsinks [http://www.pcstats.com/articleview.cfm?articleID=1116 and silver saucepans are used for cooking when cost is not an issue] {{Webarchive|url=https://web.archive.org/web/20150716233230/http://www.pcstats.com/articleview.cfm?articleID=1116 |date=16 July 2015 }}</ref> and incorporate fins to increase surface area. Heat from a relatively small component is transferred to the larger heatsink; the equilibrium temperature of the component plus heatsink is much lower than the component's alone would be. Heat is carried away from the heatsink by convective or fan-forced airflow. Fan cooling is often used to cool processors and graphics cards that consume significant amounts of electrical energy. In a computer, a typical heat-generating component may be manufactured with a flat surface. A block of metal with a corresponding flat surface and finned construction, sometimes with an attached fan, is clamped to the component. To fill poorly conducting air gaps due to imperfectly flat and smooth surfaces, a thin layer of [[thermal grease]], a [[Thermally conductive pad|thermal pad]], or [[thermal adhesive]] may be placed between the component and heatsink.

Heat is removed from the heatsink by [[convection]], to some extent by [[Radiative cooling|radiation]], and possibly by [[Thermal conduction|conduction]] if the heatsink is in thermal contact with, say, the metal case. Inexpensive fan-cooled [[aluminium]] heatsinks are often used on standard desktop computers. Heatsinks with [[copper]] base-plates, or made of copper, have better thermal characteristics than those made of aluminium. A copper heatsink is more effective than an aluminium unit of the same size, which is relevant with regard to the high-power-consumption components used in high-performance computers.

Passive heatsinks are commonly found on older CPUs, parts that do not dissipate much power (such as the chipset), computers with low-power processors, and equipment where silent operation is critical and fan noise unacceptable.

Usually a heatsink is clamped to the integrated heat spreader (IHS), a flat metal plate the size of the CPU package which is part of the CPU assembly and spreads the heat locally. A thin layer of thermal compound is placed between them to compensate for surface imperfections. The spreader's primary purpose is to redistribute heat. The heatsink fins improve its efficiency.

[[File:Memoria DDR3 Patriot Viper PVS34G1333LLK - 2.JPG|thumb|Memory modules fitted with a finned heatsink]]
Several brands of DDR2, DDR3, DDR4 and DDR5 DRAM memory modules are fitted with a finned heatsink clipped onto the top edge of the module. The same technique is used for video cards that use a finned passive heatsink on the GPU.

Higher-end M.2 SSDs can be prone to significant heat generation, and as a result these may be sold with a heatsink included, or alternatively a third-party heatsink may be attached by the user during installation.

Fan-cooled aluminium heatsinks were originally the norm for desktop computers, but nowadays many heatsinks feature copper base-plate, copper base-circle, or are entirely made of copper.

Dust tends to build up in the crevices of finned heatsinks, particularly with the high airflow produced by fans. This keeps the air away from the hot component, reducing cooling effectiveness; however, removing the dust restores effectiveness.