Front Side Bus - Which denotes the speed at which your processor interacts with the components on the motherboard. Typically the FSB is 100Mhz or 133Mhz, but overclockers often manipulate this value to increase the speed at which their processor runs. i.e. 100Mhz FSB X 5.0 clockmultiplier = 500Mhz processor. Found on https://www.encyclo.co.uk/local/22026