System and method for information handling system power management by variable direct current input

A power manager of an information handling system selectively commands a first or second source voltage from an AC-to-DC adapter based upon power consumption of the information handling system. A lower direct current voltage is provided during reduced power consumption so that DC-to-DC conversion in a power supply is more efficient. A higher direct current voltage is provided during increased power consumption so that the current required to provide the increased power remains below a threshold current, thus allowing the power system to have components that operate at lower current levels under high power consumption operations yet with increased efficiency during low power consumption operations.