FSB vs BUS Easy question

OK using CPU-Z i know i am running 100 mhz FSB and 200 mhz bus. What the difference between bus and FSB?

System:
MSI KT4VL
AMD 2100 XP thourobred B0
DDR PC2100 RAM
RADEON 98000

i am trying to get my processor to run its stock speed. It is only running 1250 mhz which is way to low.

thankyou

ok i get that FS is the speed which corrolates with my ram. I am running PC2100 ram in dual channel mode so they down clock to 133mhz. INstead of there rated 266mhz because thats all the bandwidth they need. correct? The thing i cant understand isn why my cpu is clocked down to 100 mhz when it should be running 266mhz FSB i believe. I am taking my fan off ATM to check my OPN

your fsb has a clock speed of 100. your chipset/cpu interface sends data twice each clock cycle, giving the performance of a 200 MHz bus.

your DDR (Double Data Rate) memory, like your cpu fsb, performs operations twice each clock cycle. consequently, ram running at 133 mhz yields actual performance of a 266 mhz bus.

hope this helped