As always, be careful when editing the registry and do the following:
While in Windows in RAID mode make the following registry change
Start REGEDIT and look for this line :
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\StartOverride
Change the 0 DWORD value from 3 to 0.
Then reboot into the BIOS and make the change to AHCI.
On the next startup Windows will load using AHCI mode.