All the craziness going on with XP’s SP3 and AMD processors is complex, but Microsoft wants you to know it’s not their fault, it’s HP’s fault, among others.
It turns out that the OEMs, including HP, have been installing the wrong sysprep before XP, using an sysprep designed for Intel’s platform. So it’s not a Microsoft issue, or an AMD issue, it’s a configuration issue.
There’s no patch yet, though Microsoft is working on the problem. We’ll let you know when there’s a fix.