I slipstreamed the drivers into a Windows XP cd. Reinstalled the OS on an older non-AHCI machine to recreate a base image. The image works on the older stuff, but still not with he AHCI machines. Any idea what I'm not doing right?

I can use the new XP disk to install the OS on the AHCI systems just fine. That made me think that if I built a new image, the drivers would be included from now on and work for both machine types on a single image.