Running a processor at high clock speeds allows for better performance. However, when the same processor is run at a lower frequency, it generates less heat and consumes less power. In many cases, the core voltage can also be reduced, further reducing power consumption and heat generation. This can conserve battery power in notebooks, extend processor life, and reduce noise generated by variable-speed fans. By using SpeedStep, users can select the balance of power conservation and performance that best suits them, or even change the clock speed dynamically as the processor burden changes.
For example, a Pentium M processor marketed at 1.5 GHz can run at speeds between 600 MHz and 1.5 GHz, in 300 MHz increments using SpeedStep III. Older processors, using older versions of the SpeedStep technology, have fewer increments, such as the Pentium 4-M. For example, a 1.7 GHz Pentium 4M can run at 1.6 GHz, at 1.2 GHz, and at 786 MHz.
SpeedStep technology is partly responsible for the reduced power consumption of Intel’s Pentium M processor, part of the Centrino brand.