Thermal reduction and voltage adjustment techniques for computing systems and processing devices are presented herein. In a first example, a method of operating a voltage control system for a processing device includes operating the processing device in a computing assembly at a selected performance level, the processing device supplied with at least one input voltage at a first voltage level. The method includes monitoring thermal information associated with the computing assembly, and when the thermal information indicates a temperature associated with the computing assembly exceeds a threshold temperature, adjusting the at least one input voltage level supplied to the processing device to a second voltage level lower than the first voltage level and continuing to operate the processing device at the selected performance level.