Editing Underclocking (section)

===CPU underclocking===
For microprocessors, the purpose is generally to decrease the need for [[Computer cooling|heat dissipation devices]] or decrease the electrical [[CPU power dissipation|power consumption]]. This can provide increased system stability in high-heat environments, or can allow a system to run with a lower airflow (and therefore [[Quiet PC|quieter]]) cooling fan or without one at all. For example, a Pentium 4 processor normally clocked at 3.4&nbsp;GHz can be "underclocked" to 2&nbsp;GHz and can then be safely run with reduced fan speeds. This invariably comes at the expense of some system performance. However, the proportional performance reduction is usually less than the proportional reduction in clock speed because performance is often limited by other bottlenecks: the [[hard disk]], [[Graphics processing unit|GPU]], [[disk controller]], [[Internet]], [[computer network|network]], etc. Underclocking refers to alterations of the timing of a synchronous circuit in order to lower a device's energy needs. Deliberate underclocking involves limiting a processor's speed, which may affect the speed of operations, but may or may not make a device noticeably less able, depending on other hardware and desired use.

Many computers and other devices allow for underclocking. Manufacturers add underclocking options for many reasons. Underclocking can help with excessive heat buildup, because lower performance will not generate as much heat inside the device. It can also lower the amount of energy needed to run the device. Laptop computers and other battery-operated devices often have underclocking settings, so that batteries can last longer without being charged.

In addition to providing underclocking features, manufacturers can choose to limit the capability of a machine in order to make it more efficient. Reduced instruction set computer (RISC) models can help makers build devices that work on less power.