A graphics processing device implementing a set of techniques for power management,
preferably at both a subsystem level and a device level, and preferably including
peak power management, a system including a graphics processing device that implements
such a set of techniques for power management, and the power management methods
performed by such a device or system. In preferred embodiments, the device includes
at least two subsystems and hardware mechanisms that automatically seek the lowest
power state for the device that does not impact performance of the device or of
a system that includes the device. Preferably, the device includes a control unit
operable in any selected one of multiple power management modes, and system software
can intervene to cause the control unit to operate in any of these modes.