It looks like some OEM manufactures (HP in particular) have been using a single image for their XP installs for all hardware platforms, be it Intel or AMD. They have got away with this despite the fact the image installs Intel drivers on AMD machines.
However, there is a major issue when it comes to installing service packs and the new release of SP3 for XP has resulted in a lot of users unable to boot into Windows with the machine continually rebooting (it’s actually Blue-Screening, but the default reset hides this).
I’d say this is mostly the OEM’s fault for not creating the correct images for the PCs they ship, but Microsoft have some of the blame too for not blocking the SP3 release on Windows Update for those OEM installs known to be a problem. Especially as MS has known about this apparently since SP2, and also the beta and RC releases of SP3 !!
The problem now is many people will end up with unbootable PCs and not have a clue what to do. In some cases it is recoverable via safe mode, but not always, and the suggested “fix” can also render the machine in an even worse state. Many will likely be out of warranty now too, even though they may only be a couple of years old.