CPU cooling
CPUs with great thermal dissipation have to be cooled. This can be done passively by a large heatsink or actively, i.e. by a heatsink and a fan, the latter one circulating air through the heatsink (see aircooling).
Over the years, CPU cooling has become more sophisticated. Today, high-end processors are dissipating over 100 watts of heat on a surface of <80mm², which requires extensive cooling. Whereas Aluminium was a quite common material for heatsinks some years ago, today many heatsinks feature copper baseplates or are entirely made of copper.
Watercooling, Peltier cooling and heatpipe cooling have become popular amongst overclockers and silence enthusiasts who want their computers to run without the need for high-volume (and often noisy) fans.
