Those settings are for overclocking the CPU. Is this something you really want to do? If yes, then do some research on the subject.
The default setting is 100 (100 x 4 = 400 bus speed). 400 x 5.5 cpu multiplier = 2200 MHz
CPU multiplier is fixed and cannot be changed.
100-133 FSB supports PC2100 memory. If you try to overclock, you need faster memory. If you have PC2700 memory, you can push FSB to 166 and memory will still work.
