PC Heatsinks and CPU Cooling

Processors and other high-power chips generate heat as they work, and if that heat is not removed they can become unstable or be damaged. A heatsink is a passive cooling device that draws heat away from a chip and spreads it over a large surface area, where it can be carried off by the surrounding air. Heatsinks are made from metals with good thermal conductivity, typically aluminium or copper, and are pressed against the chip with a thin layer of thermal paste to fill tiny gaps and improve heat transfer.

The shape of a heatsink is designed to expose as much surface as possible to moving air. Extruded heatsinks are made by forcing aluminium through a die to form a continuous profile of fins, which is an economical way to produce many parallel fins. Folded-fin heatsinks instead attach a thin, repeatedly folded sheet of metal to a base, allowing very closely spaced fins and a large surface area in a compact form. A fan is often added to force air across the fins, greatly increasing the rate at which heat is removed.

Some systems use thermoelectric cooling, based on the Peltier effect, in which passing an electric current through a junction of two materials makes one side cold and the other hot. A Peltier cooler can pull heat away from a chip and pump it to a heatsink, allowing temperatures below those a heatsink alone could reach. However, these devices consume significant power and produce extra heat that must itself be removed, so they are used selectively rather than in typical machines.

Frequently asked questions

What does a heatsink do?

It draws heat away from a chip and spreads it over a large finned surface, where the surrounding air can carry the heat away.

What is the difference between extruded and folded-fin heatsinks?

Extruded heatsinks are formed by pushing metal through a die to make fins, while folded-fin types use a folded metal sheet to pack fins more closely.

How does a Peltier cooler work?

It uses an electric current through a junction of two materials to make one side cold, pumping heat away from a chip, though it consumes power and generates extra heat.