The new 550MHz mobile Celeron is targeted at low-cost mobile PCs, and as such, runs at only 66MHz with only 128K of cache. SpeedStep is an Intel technology that allows processors to dynamically switch clock frequency and voltage, depending on whether the computer is running on batteries or is plugged into the wall. The changes in frequency happen in only 1,2000th of a second.
Users can also select which mode to via an icon located at the bottom of the screen.
No reboot is required when switching modes.