A computer system adapted to connect a plurality of external servers is provided. The computer system includes a motherboard module, a power supply module, a baseboard management controller (BMC), a control module and a plurality of graphics processing units (GPUs). The motherboard module includes a plurality of first connectors and a plurality of second connectors, wherein the second connectors are respectively connected to the external servers. The power supply module is coupled to the motherboard module for supplying power to the computer system. The control module is disposed on the motherboard module, and the control module manages corresponding relations of the first connectors and the second connectors, and controls the power supply module to supply power to the first connectors. The GPUs are respectively coupled to the first connectors. Each of the GPUs correspondingly expands a computing capability of the external server through the corresponding second connector.