The subject matter of this application is embodied in an apparatus that includes a data processor, and two or more hardware monitors to measure parameters associated with the data processor. The apparatus also features a power supply to provide power to the data processor and the hardware monitors, and a controller to control the power supply to adjust an output voltage level of the power supply according to measurements from the hardware monitors. Different weight values are applied to the hardware monitors under different conditions, and the power supply output voltage level is controlled according to weighted measurements or values derived from the weighted measurements.