Methods, computing systems and computer program products implement embodiments of the present invention that include determining a required electrical power level for one or more computer elements. Upon selecting a first value indicating a first electrical power level that is less than the required electrical power level, the first value is conveyed to a first power supply unit (PSU), so that that the first PSU delivers, to the one or more computer elements, the first electrical power level. A second value is selected that indicates a second electrical power level that is different from the first value, the second value indicating a difference between the required electrical power level and the first electrical power level. The second value is conveyed to a second PSU, so that that upon receiving the second value, the second PSU delivers, to the one or more computer elements, the second electrical power level.