How to install the AHCI/RAID drivers for the M4A77TD/AMD south bridge sb710 under WinXP

The AHCI drivers allow you to use your SATA drives in AHCI or RAID mode, as opposed to legacy IDE mode. 

Finding the AHCI drivers is a real pain, as they are stored in the "ASUS Make AMD RAID/AHCI Driver Disk" zip file on the ASUS download site for the M4A77TD. You can also get the same exact drivers from
http://game.amd.com/us-en/drivers_catalyst.aspx?driver=Integrated/xp32-chipset, under "Raid Driver".

Since there is no floppy drive controller, it is particularly hard to use this "make disk" tool so that the driver can be loaded during install. There's probably a way using a USB thumb drive, but I haven't attempted it.  It's much easier, but still rather obscure, to add this driver after you have installed (which means your main hard drive must be in IDE mode).

First, extract the files and save the WINXP/x86 folder to your desktop. Then open the Windows Device Manager (under the hardware tab of System Properties). Scroll down to the Unrecognized PCI device with a big question mark, and the proceed to update its driver (why couldn't they at least give it a more descriptive name??).

Tell windows to use the INF file from the WINXP/x86 folder on your desktop. You'll need to tell it that it's a RAID driver, or it won't recognize that you've found the right file. Ever so annoyingly, Windows also offers the option to "install", when you right click on the ahcix86.inf file in the x86 folder, but trust me, this does nothing. When you've actually installed the driver, the hard drives will immediately become available.