The drivers you're looking for specifically *are* the AHCI drivers, otherwise known as the Intel Matrix Storage Manager
On the left, click "Download Intel® Matrix Storage Manager Software", and then pick Windows XP Professional. You'll be given a list of driver packages. The one you want is:
32-bit Floppy Configuration Utility (202KB) -- 126.96.36.1997 -- 1/9/2009
Unpack the ZIP file to a floppy disk, or slipstream the files (if you make your own XP CDs). Either method works. This will add support for AHCI mode, and BIOS-level RAID (which uses AHCI as well).
If you use the F6 floppy method, or the slipstreaming method, you might be given a list of controllers/modes to choose from. I'm pretty sure the one you want will be labelled:
Intel(R) ICH10R SATA AHCI Controller
I've done this on my Asus P5Q SE board (which uses the ICH10, not the ICH10R). The P5Q SE (not /R) supports AHCI mode, but not RAID.
One thing to keep in mind: this *will* require a complete reinstall of the OS
, because the base device naming scheme in Windows changes. Otherwise, you'll get a bluescreen, as the above Intel URL documents.
Finally, you do not need "Asus's drivers" -- you can (and should) safely use Intel's site for this. There is nothing Asus-specific about the ICH10 or ICH10R.
EDIT: One thing to point out: if you don't have the P5Q SE/R, then there's not much advantage to using AHCI mode unless you plan on hot-swapping disks in your machine (in which case AHCI is definitely what you want). You can leave the BIOS option set to IDE, and you will still achieve SATA300 speed. I've benchmarked both modes on XP, and there's really not much of a difference. On FreeBSD or Linux, I would *highly* recommend using AHCI.--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.