Where the Expansion Bus fits in

•          Connects to either Northbridge or Southbridge depending on motherboard

•          All devices soldered to the motherboard run at the speed of the motherboard e.g. 133 Mhz

•          This doesn’t work for expansion cards

•          IBM designed the external data bus to run at it’s own standardized speed

•          In the IBM XT PC, the expansion bus ran at 7 Mhz