Definitions for "System board"
n. In a personal computer (PC), the main circuit board that supports a variety of basic system devices, such as a keyboard or a mouse, and provides other basic system functions.
The main circuit board of the computer that contains the CPU, the RAM, the SBus, the ports, the BIOS, and expansion slots. (Also called motherboard.)
A microcomputer circuit board that contains the microprocessor, electronic circuitry for handling such tasks as input/output signals from peripheral devices, and memory chips (same as motherboard).