Editing Computer cooling (section)

==Generators of unwanted heat==
[[Integrated circuit]]s (e.g. CPU and GPU) are the main generators of heat in modern computers. Heat generation can be reduced by efficient design and selection of operating parameters such as voltage and frequency, but ultimately, acceptable performance can often only be achieved by managing significant heat generation.
[[Image:Laptop dust.jpg|right|thumb|The [[dust]] buildup on this laptop CPU heatsink after three years of use has made the laptop unusable due to frequent thermal shutdowns.]]
In operation, the temperature of a computer's components will rise until the heat transferred to the surroundings is equal to the heat produced by the component, that is, when [[thermal equilibrium]] is reached. For reliable operation, the temperature must never exceed a specified maximum permissible value unique to each component. For semiconductors, instantaneous [[junction temperature]], rather than component case, heatsink, or ambient temperature is critical.

Cooling can be impaired by:
* '''Dust''' acting as a thermal insulator and impeding airflow, thereby reducing heatsink and fan performance.
* '''Poor airflow''' including [[turbulence]] due to friction against impeding components such as [[ribbon cables]], or incorrect orientation of fans, can reduce the amount of air flowing through a case and even create localized whirlpools of hot air in the case. In some cases of equipment with bad thermal design, cooling air can easily flow out through "cooling" holes before passing over hot components; cooling in such cases can often be improved by blocking of selected holes.
* '''Poor heat transfer''' due to poor thermal contact between components to be cooled and cooling devices. This can be improved by the use of [[#Thermally conductive compounds|thermal compounds]] to even out surface imperfections, or even by [[#Heat sink lapping|lapping]].