Stop Grant state

Stop Grant mode is a low-power state supported by majority of modern x86 microprocessors. Switching to this mode is controlled by hardware. When in this state, the CPU has internal clock running and may respond to interrupts and other signals. The CPU may transition from Stop Grant state to Normal state, AutoHalt mode and Sleep mode. Power savings in this mode can be significant - from 50% for Pentium 4 Northwood and higher for other processors, and are usually the same as power savings provided by AutoHalt mode.

Please note that although processor's clock is not stopped in this mode, the CPU effectively is not running, i.e. not executing any instructions.