CPU speed is overrated, IMO. Lots of marketing hype. What is more important than clock speed is the processor's cache size.
If I am a believer of clock speed, I wouldn't have asked in the first place. Afterall fastest P4 runs over 3G and fastest XP runs 2.15G not taking overclocking into consideration. According to AMD website, XP3200+ runs faster than fastest P4 in all benchmark tests. The only applications comes close is multimedia. That doesn't surprise me because old clumsy CISC architecture allows Intel to put in special multimedia instruction sets. I am going trust it because the publication is from a 3rd party. I have noticed Intel website does not have a single white paper on performance comparisons against rival processors while AMD website is full of them. To me that means Intel is not proud of their processor performance and therefore admit the defeat.