Some embodiments of a processing device include one or more power supply monitors to provide one or more counts representative of one or more operating frequencies of one or more circuit blocks based on a voltage supplied to the circuit block(s). Some embodiments of the processing device also include a system management unit to determine an initial voltage supplied to the circuit block(s) based on a target count and to reduce the voltage supplied to the circuit block(s) from the initial voltage in response to the count(s) generated by the power supply monitor(s) exceeding the target count.