A motherboard includes a printed circuit board (PCB), a central processing unit (CPU), a regulator, a first memory adaptor, and a second memory adaptor. The PCB includes a top surface, a bottom surface, a plurality of first soldering pads and first leads arranged on the top surface, and a plurality of second leads arranged between the top surface and the bottom surface. The PCB defines a plurality of first vias, second vias, and power vias. The CPU is connected to the first vias. The voltage regulator is connected to the power vias. The first memory adaptor neighbors to the regulator and is surface-mount soldered to the first soldering pads. The first soldering pads are connected to the first vias by first leads. The second memory adaptor is soldered to the second vias. The second vias are connected to the first vias by the second leads.