SpeedStep

A feature available with Intel Pentium III, Pentium III-Mobile, Pentium 4-Mobile, and later Intel mobile processors that allows a user to control features of the processor through software that lower its speed. By reducing the overall speed of the processor it helps conserve power and reduce the heat produced by the processor, which saves on battery life.
If you're looking for software or drivers relating to SpeedStep for your computer running versions of Microsoft Windows 2000 or earlier you must contact the computer manufacturer. Intel does not provide any software for this feature.