I made a post about this a while back...I'll try and remember it...
Your Varibles: CPU Speed: S, RAM Speed: R, CPU Mulitplier: M HTT Speed:H RAM Divider (as a fraction of 1): D.
R=(S/[M/{D}])
For, say an A64 3200+ you have a CPU speed of 2000, a 10x CPU multi, and a 1:1 ram divider. So... 200=(2000/[10/{1}]), it checks out. Say you're running at 2.4 though, and your RAM doesn't OC well, so you put up a 5/6 ram divider.
(2400/[10]/{.83}])=R Simplifes down to 2400/12=200. See?