Change from IDE to AHCI mode in Windows 7

If you already have Windows 7 installed and choose to upgrade to a new SSD then you will definetly want to take advantage of the benefits that AHCI has to offer.

Once you change it in your BIOS from IDE to AHCI on the drive controller you have probably found that Windows 7 will blue screen and will not load.  This is because any drivers that are not needed are not activated in Windows 7.

To give an example of the performance difference take a look at this photo.  This was taken when my drive was set to IDE.

Now take a look once it was changed over to AHCI.  MASSIVE performance difference.

To make this change 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.

1. Click Start, type regedit in the Start Search box, and then press ENTER.

1. If you receive the User Account Control dialog box, click Continue.

1. Locate and then click one of the following registry subkeys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV

1. In the pane on the right side, right-click Start in the Name column, and then click Modify.

1. In the Value data box, type 0, and then click OK.

1. On the File menu, click Exit to close Registry Editor.

Microsoft also has a FIX-IT you can run to do the same thing if you're uneasy with making changes to the registry.

As always make sure you have good backups before you begin.

Good luck.