Generally, the bios has 3 settings for SATA transfer mode. IDE mode should be avoided with any modern drive. AHCI is the right choice if you have only single drives, and RAID is the right choice if you want to run a RAID array. On almost all motherboards, RAID mode also enables AHCI, so going from RAID to AHCI would do nothing other than simply eliminating the RAID array.
Oh, and screw you too