What is a CPU (central processing unit) heat sink, and how does it fix an overheating, slow PC?

A CPU heatsink is a metal or composite device directly attached to the CPU that serves to conduct heat away from the chip and thereby provide cooling. This is one of the most vital parts of computer hardware and, oftentimes, is one of the largest and most obvious pieces of equipment on the motherboard. Some of these devices have fans integrated that allow even more efficient cooling. These are not user-serviceable devices though troubleshooting them is fairly easy and adding a better device may improve computer performance.

The most identifiable part of a heatsink is the metal conductor component. This will generally have a very complex geometry to it, including fins and vents. This serves to increase the surface area of the heatsink and, thus, the amount of heat that can be transferred from the component to the air surrounding the device. Heatsinks are usually attached to the CPU itself with a combination of a thermal paste which provides a secure bond and conducts heat and a mechanical device that holds the heatsink in place. A secure connection is vital to proper performance.

A CPU functions faster and with more stability when the operating temperature is kept in the optimal range. Particularly intensive tasks cause these components to heat up fast and, without proper cooling, performance will degrade when the temperature exceeds acceptable levels. The heat sink is vital to this as it’s in constant contact with the component itself. The fan included on a heatsink may be a variable or always-on, model. The conducting of the component’s heat to the fins of the heatsink allows great deals of thermal energy to be disbursed into the surrounding air very quickly.

Frequent processor overheating can oftentimes be remedied by the installation of a better heatsink. Some computer enthusiasts engage in a practice called “over-clocking”. This involves running a processor at faster speeds than its designers intended, similar to substituting very high-octane fuel or nitrous oxide for gasoline in a car to make it go very fast. Over-clocking greatly increases the heat produced by a CPU and, to that end, these enthusiasts oftentimes employ very complex, powerful heatsinks to ensure that the processor survives. In regular usage, a good heat sink can mean even more of a difference in performance.

Some processors are known for their high levels of heat production. In fact, some processors had very bad reputations in their time for overheating. Oftentimes, this had more to do with the cooling system included in the design than with the processors themselves. A variety of sources can be checked to compare one’s processor with others to see if heat is a particular concern with the model in question. If it is and if performance is slow, a new heatsink may well help. Because the hottest processors are usually the very high-performance models, slow performance should be taken as an indication that there is something wrong with the processor’s set up and heat displacement should be a starting point.