thats because amd locked the 64's multipliers, so you can only change the fsb, i think. and you dont need to get the athlon's clock speed to 3 or 4ghz, because the athlons operate differently. amd's have 9 IPC (instructions per clock) and intel have 6 IPC. so for example, my 3400+ (oc'ed to 2.42) is about the same as a 3.4ghz intel non-EE. because my amd's clock speed times the IPC would give me: 21.78 and intel's 3.4ghz would be: 20.4
but ill say one thing, good choice for picking AMD.