are you talking intel or amd?
Intel is Quad pumed so here is a Exp.
Socket 775 200FSB x4 =800
Socket 775 266FSB x4 =1066
Socket 775 333FSB x4 = 1333
Socket 775 400FSB x4 = 1600
i dont know how amds HT works right off hand. i have been playing with more intel systems then amd's. and no i am not a fanboy