You see, I am always thinking in terms of Intel. I will say this: Before the P4, I was all Intel. The PIII was awesome.
But then I got my first AMD CPU, the AMD Athlon Thunderbird. 1.0Ghz CPU.
Ever since, what can I say?
Intel slacked off, AMD rules.
I have had the opportunity to test the demo on an AMD64 and it was actually pretty sweet.
Conclusion: Run it on a proper CPU. If you have a regular P4, you should be fine. If you're using Intel's attempt into the 64-Bit market, you're at a serious loss.