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    June 06

    Forgot to enable AHCI on your Windows 7 RC (or Vista) for your SSD?

     
    I was doing some reading tonight an found info implying that unless your SATA controller is set to AHCI or RAID mode (BIOS setting), performance improving things like NCQ and Trim do not work even if your SSD or hard drive (that was so 2008!) has those features available.
     
    So, of course, changing this BIOS setting and expecting everything to work is just asking a bit too much (what do you think we're talking about, a Mac?). After making this BIOS change, you will soon see a beautiful blue screen of death otherwise known as BSOD. When this occurs, you will likely be googling around for some solution to the problem (after you change that BIOS setting back and reboot) or maybe you'll try the new Microsoft Bing (I didn't). In any event, hopefully you will find this blog entry or the link I will provide that should solve your problem.
     
    http://support.microsoft.com/kb/922976 will show you how to make a registry entry change that will likely solve the problem for you. At least it did for me...
     
    Here is the relevant info from the link above:
     
    To resolve this issue, 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 the following registry subkey:
      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
    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.

    After doing this, reboot, get into the BIOS, change back to AHCI mode and eventually you will be able to login to Windows (i.e. no BSOD). At this time, Windows will figure out that is needs to install drivers for your fancy new AHCI controller that replaced your old legacy controller (which of course forces you to reboot one more time) and then you are all set.

    At least this is how it went down for me with Windows 7 RC (BTW: Windows users can be happy and proud again with Windows 7, Mac ain't got nuthing on you no more...at least until Snow Leopard comes out, then we'll just have to see...)

     

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