Enable AHCI mode afterwards

(source: http://www.patriotmemory.com/forums/showthread.php?5465-How-Do-I-Enable-AHCI-With-AMD-890-And-Win-7)

Typically, (IF you did not install AHCI initially but went with the default IDE setup) with mechanical SATA drives, the process is to do the AHCI registry hack: http://support.microsoft.com/kb/922976

Excerpt:
To resolve this issue yourself, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:

1. Exit all Windows-based programs.
2. Click Start, type regedit in the Start Search box, and then press ENTER.
3. If you receive the User Account Control dialog box, click Continue.
4. Locate and then click one of the following registry subkeys:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
5. In the right pane, right-click Start in the Name column, and then click Modify.
6. In the Value data box, type 0, and then click OK.
7. On the File menu, click Exit to close Registry Editor.

, then reboot, go into the BIOS, change to AHCI, save and reboot and all is well.