Ok well heres what i can say about it pretty much
Fsb is the way the processor speaks to the rest of the compenents in laymans terms
processor speed e.g. is calculated by the Fsb times a multiplier on the cpu chip
so e.g.
200 times by X = 3000
The X would be 15 so your cpu multiplier is 15 so data is sent and taken from the processor at 200mhz , then data is processed at 3000mhz on the processor
At least i hope that is right cos thats what i wrote for my computing homework