Computer systems components produce large amounts of heat during operation, including integrated circuits such as CPUs, chipset and graphics cards, along with hard drives. This heat must be dissipated in order to keep these components within their safe operating temperatures. This is done mainly using heat sinks to increase the surface area which dissipates heat, fans to speed up the exchange of air heated by the computer parts for cooler ambient air, and in some cases soft cooling, the throttling of computer parts in order to decrease heat generation. The faster a given CPU runs, and the higher its supply voltage, the more heat it emits. If the cooling thingy attached to the top of the chip cannot dissipate that heat well enough, the CPU will get too hot and stop working. Note that stop working does not imply and will never work again. Pretty much any cooler will stop a CPU from heating up so fast, and so far, that it is destroyed. If you run a current model CPU with no cooler at all, you can blow it up; Athlon and Duran can die in seconds, and often do when someone failed to notice that their cooler is not clipped on right and thus does not actually touch the CPU. While any method used to move air around or to computer enclosures would count as air cooling, fans are by far the most commonly used implement for accomplishing that task. The term computer fan usually may also be intended to signify any other computer fan, such as a CPU, GPU, HDD fans. Desktop computers typically use one or more fans for heat management. Almost all desktop power supplies have at least one fan to exhaust air from the case. Most manufacturers recommend bringing cool, fresh air in at the bottom front of the case, and exhausting warm air from the top rear. Data centers typically contain many racks of flat 1U servers. Air is drawn in at the front of the rack and exhausted at the rear. Because data centers typically contain such large numbers of computers and other power consuming devices, they risk overheating of the various components if no additional measures are taken. Laptops are typically made to rest on a solid surface. Unfortunately, a flat surface is the least desirable angle to dissipate heat, and lower temperatures are achieved by a chimney effect when a laptop is set at an angle from horizontal. It is important to note that laptops are neither designed for nor should they be used on surfaces or in spaces which impede the free flow of air (such as carpet or bed linens), as heat damage and/or thermal shutdown/slow down may occur.