OK fair enough but would be wary of mixing FSB's mate - as if yer CPU is running at 400 and RAM at 333, there could well me issues cos the CPU running quicker then the ram could handle, and normally you would down throttle the CPU to run @ 333....
Bsaically best thing is to try for a 333 FSB CPU although, if you were planning to upg the ram in the future it may be best to go for 400 but "down grade" to 333......