Depends on what you're doing. In video encoding, which requires fast clockspeeds and a large cache, yes, the Pentium 4 would probably beat the A64. In office applications, like Word/Excel/(Basically ANY office application), which don't require any fast clockspeeds or large caches, they would be the same. In videogames, which require a efficient architecture, and are helped by AMD's onboard memory controller, the A64 would kick the Pentium 4's a$$.
You tell me. What's more important? Video Encoding or Video Games?