Computer Cooling - Generators of Unwanted Heat

Generators of Unwanted Heat

Integrated circuits (e.g., CPU and GPU) are the prime 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 accepting significant heat generation.

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, i.e., thermal equilibrium is reached. For reliable operation, the temperature must never exceed a specified maximum permissible value for each component. For semiconductors, instantaneous junction temperature, rather than component case, heatsink, or ambient temperature is critical.

Cooling can be hindered by:

• Dust acting as a thermal insulator and impeding airflow, thereby reducing heat sink and fan performance.
• Poor airflow including turbulence due to friction against impeding components such as ribbon cables, or improper 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 thermal compounds to even out surface imperfections, or even by lapping.