I've installed the recommended patches, but AH still freaks out when I run it in native XP mode. I've been running it just fine in Windows 95 compat mode for the last year and a half, but for whatever dumb reason no matter what I've tried I just can't get it working correctly in the native multi-core-using mode.
I've got an AthlonX2 4400, and I use a Geforce 8800gtx graphics card running at 1920x1200 on my 24" lcd. Mind, this is almost always sufficient, with my framerate usually pegged at 60fps (I've got it set to 60 fps because that's what my lcd screen updates at), but I've had situations with massive numbers of planes within visual range where I dropped down into framerates low enough to be a distraction. Not very often, but it has happened.