A motherboard including a socket and a memory slot is provided. The socket is adapted for disposing a processor with at least one memory channel, and each of the memory channels supports at least two memory cards. The memory slot is coupled to the socket and transmits signals from the memory channel. The memory slot includes a plurality of pins. A first part of the pins of the memory slot is assigned to transmit a signal from one of the memory cards supported by the memory channel, and a second part of the pins of the memory slot is assigned to transmit a signal from another one of the memory cards supported by the memory channel.