How data flows through a Motherboard
The chipset consists of two main components, the North- and South- Bridge chips, which are connected over the PCI bus. The CPU, Memory and AGP talk to the Northbridge and the Southbridge handles all the I/O, including the ISA bus.
The link between the CPU and Northbridge is called Front-side bus, which is (usually) the same speed as the Memory Bus, and can be varied, as when overclocking. The Back-side bus connects the CPU with L2 cache.
