Did you already install the OS? If so changing it after the fact will probably cause a corruption.
BIOS:
** Assumes the SSD is connect to the ICH9R **
SATA RAID/AHCI Mode = {Enabled}
SATA Port0~3 Native Mode = {Enabled}
Save & Exit
Registry ->
http://support.microsoft.com/kb/922976
Caveat:
"To enable hot plug capability for the SATA connectors (SATAII0, SATAII1, SATAII4, SATAII5) controlled by the ICH9 South Bridge, you must install Windows Vista (on ICH9, hot plug is supported in Windows Vista only) and configure the SATA connectors for AHCI mode. The requirements above do not apply to the SATA connectors (GSATAII0, GSATAII1) controlled by the GIGABYTE SATA2 controller. (Refer to Chapter 2, "BIOS Setup," "Integrated Peripherals," for details on enabling AHCI.)"