Well.. this is essentially what you need to know:
Computer performance is measured in Instructions per second (IPS) and NOT cycles per second (in GHz) (CPS)...
A lot of people falsely think that CPS is the correct measure of the "power" of a CPU.. How are they related?
Instructions per second = Cycles per second x instructions per cycle
AMD has a smaller CPS than Intel for "equivivalent" CPUs. But this is 1/2 of the performance measure as u can see from the above equation. The "instructions per cycle" is HIGHER in AMD typically. This offsets the lower CPS.
If you don't understand what a "instructions per cycle" is, just do a search with that keyword for one of my old posts. I am sure I've described it before.