system bus - Computer Definition
(1) The primary pathway between the CPU and memory. The speed is derived from the number of parallel channels (16 bit, 32 bit, etc.) and clock speed. Also known as a "frontside bus," it is faster than the peripheral bus (PCI, ISA, etc.), but slower than the backside bus. See peripheral bus, backside bus and Northbridge.
(2) The primary pathway between the CPU and peripherals. See peripheral bus.