The processor speed is slower than expected on a notebook computer that is running Windows XP

When you start a laptop computer on battery power, the processor speed may be slower than the processor speed that the manufacturer indicates. To view the processor speed, you can use the System tool in Control Panel.

This behavior occurs because most laptop computers on battery power set the processor speed to a slower speed to conserve battery power and to reduce the temperature of the processor.

This behavior depends on the capability of the processor and the BIOS settings for the laptop computer. When the computer starts to use battery power, the processor speed is automatically reduced and written to the following registry key:

This behavior is by design.