XP should install on any processor. I'm using XP on my i7-2600K perfectly fine. If you're having problems, then it could be that your motherboard, video card, etc. doesn't have an XP driver available. Check that first.
Edit: do note that with XP (unless you have the 64-bit edition), you won't be able to use much more than 3 GB of RAM. That's really about the only issue you should have, outside the complete lack of XP drivers (you can always check for a download from the manufacturer). Also, if you have an OEM version from another computer, you won't be able to use it. If you have the retail version, you can, provided you no longer use that previous computer (you're transferring the license).