CPU Fan

A computer fan is any fan inside, or attached to, a computer case used for active cooling, and may refer to fans that draw cooler air into the case from the outside, expel warm air from inside, or move air across a heatsink to cool a particular component.

Usage of a cooling fan

As processors, graphics cards, RAM and other components in computers have increased in speed and power consumption, the amount of heat produced by these components as a side-effect of normal operation has also increased. These components need to be kept within a specified temperature range to prevent overheating, instability, malfunction and damage leading to a shortened component lifespan.

While in earlier personal computers it was possible to cool most components using natural convection (passive cooling), many modern components require more effective active cooling. To cool these components, fans are used to move heated air away from the components and draw cooler air over them. Fans attached to components are usually used in combination with a heatsink to increase the area of heated surface in contact with the air, thereby improving the efficiency of cooling.

CPU fanUsed to cool the CPU (central processing unit) heatsink. Effective cooling of a concentrated heat source such as a large-scale integrated circuit requires a heatsink, which may be cooled by a fan; use of a fan alone will not prevent overheating of the small chip.

Used to cool the heatsink of the graphics processing unit or the memory on graphics cards. These fans were not necessary on older cards because of their low power dissipation, but most modern graphics cards designed for 3D graphics and gaming need their own dedicated cooling fans. Some of the higher powered cards can produce more heat than the CPU (dissipating up to 289 watts), so effective cooling is especially important. Passive coolers for new 3D video cards such as the Thermalright HR-03 are rarer.

Used to cool the heatsink of the northbridge of a motherboard's chipset; this may be needed where the system bus is significantly overclocked and dissipates more power than is usual, but may otherwise be unnecessary. As more features of the chipset are integrated into the central processing unit, the role of the chipset has been reduced.

Fans are, less commonly, used for other purposes such as:

• PCI slot fan: A fan mounted in one of the PCI slots, usually to supply additional cooling to the PCI and/or graphics cards.
• Hard disk fan: A fan mounted next to or on a hard disk drive. This may be desirable on faster-spinning hard disks with greater heat production. As of 2011 less expensive drives rotated at speeds up to 7,200 RPM; 10,000 and 15,000 RPM drives were available but generated more heat.
• CD burner fan: Some internal CD and/or DVD burners included cooling fans.