I *owned* an AMD Athlon XP 3000+, and recently UPGRADED to the Intel Pentium 4 2.8GHz (with H/T), and am a lot happier with it.
I've always been on Intel and decided to try the Athlon, only to find how bad it performed.
It may have been the motherboard, who knows. All I do know is that the Intel works a lot better for me now.