An exemplary motherboard includes a first slot arranged for mounting a first type of memory, a second slot arranged for mounting a second type of memory, a voltage regulator electronically connected to the first slot and the second slot, and a serial presence detect (SPD) unit connected to the voltage regulator. The first memory and the second memory alternatively mounted on the motherboard, the SPD detects which type of memory is mounted on the motherboard, and the voltage regulator outputs voltages suitable for the type of the memory mounted on the motherboard according to a detection result of the SPD.