I prefer AMD64!

For most application, you could not find the different.
But for some application, AMD64 is two times faster than
P4 who has the same speed. The reason is AMD64 has 1024K Level 2 cache but P4 has 512K Level 2 cache.
If you just use it as a desktop to run office application or game, you could not tell the different. But if you want
to run it as a computation horse, you may try AMD64.
We test dual Althon MP, Intel P4 2.8G, Xeon 2.4G and AMD64
2.2G. The AMD64 us the fastest one.