EG45M-UD2H mobo, Windows XP, with a single SATA drive.
AHCI installation for Windows XP for single Sata may be tricky, while there are 3 options - disable, AHCI or Raid and one picks AHCI.
Windows XP setup failed with BSOD 0x0000007B, when set just to AHCI. (While was successful with Vista).
Windows XP installation was successful only when set to RAID.
The BIOS direct ACHI setting incompatibily with Windows XP may be a problem with most Intel matrix Storage chipsets.
More information is welcomed.
It's always wise to get use of a full Sata command set and full speed of Sata.