Separate power island for high performance processor. A multi-processor design is presented in which each of the processors is implemented in separately powered portions of a circuitry (e.g., an integrated circuit). One of the processors can be a main application processor, and another of the processors can be a baseband processor. In addition, the each of the processors can be implemented using different types of circuitry (e.g., one of the processors [such as the main application processor] is implemented using higher performance/higher leakage circuitry that another of the processors [such as the baseband processor]). One of the processors (e.g., main application processor) can be powered down when not needed thereby providing energy/power conservation which can be vital is handheld communication device applications such as wireless handheld communication devices.