1. A method for optimizing a core voltage level of a portable computing device and enhancing frequency performance of individual subsystems, the method comprising: determining a plurality of voltage values for a plurality of subsystems within the portable computing device, wherein at least one subsystem is a multiplexed subsystem comprising a plurality of processing engines; calculating a reduced set of voltage values based on the plurality of voltage values; determining an optimized voltage level for a shared power domain within the portable computing device from the reduced set of voltage values; setting the shared power domain to the optimized voltage level; determining that the optimized voltage level exceeds a required voltage level for the at least one multiplexed subsystem when running the plurality of processing engines; identifying a subset of the plurality of processing engines; and processing a workload of the at least one multiplexed subsystem with the subset of processing engines.