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I just purchased a 2TB Fantom USB2/eSATA external hard drive. Unfortunately it revealed my oversight when my first custom system was built last Summer. I installed Vista Home Premium 64bit in IDE mode (default in Bios) instead of the ACHI mode, which would not only provide Native Command Queuing but also hot plug of external hard drives I need now.

As expected when I changed the Intel controller to ACHI in BIOS the system won't boot anymore as expected.

My motherboard is a Gigabyte GA-EX58-UD4P. Both my internal 750GB WD Black caviar 7200rpm Hard Drive and my eSATA bridge (providing 2 eSATA external connection) are connected on three of the six Intel SATA connectors controlled by the ICH10R (South Bridge) controller.

The internal hard drive is on SATA0 and eSATA connectors on SATA4 and SATA5. The two SATA connctecor controlled by Gigabyte controller (i.e. GSATA0 and GSATA1) are not used.

EDIT: The external hard drive driver just installed out of the sudden on my last try as I was writing this post and after I tried to install SATA/RAID drivers while under Windows from Gigabyte website for both Gigabyte and Intel controllers. Note that Intel setup from MSM/iata_cd.exe gave me an error that my system did not meet the minimum requirement and closed.
The new external SATA hard drive is now reported along with the internal hard drive in Device Manager under the IDEATA/ATAPI Controllers, with Intel(R) ICH10 Family controller Serial SATA controller.

I am about to upgrade to Windows-7 Home Premium 64Bit, for which I'd like all SATA drive to operate in AHCI mode. It would allow my external hard drive with an eSATA connection to support hot-plugging and seems beneficial for the internal hard drive too, while multi-tasking.

Enabling the AHCI mode after a Vista install with IDE mode enabled does not seem trivial in the few solution I read - and a little confusing. Any suggestions from experienced users would be greatly appreciated.


  • Should I enable AHCI mode before (i.e. under Vista) or during the upgrade to Windows-7?

  • If you recommend it is done before, can I enable the ACHI mode without re-installing VISTA?

Also, I have multiple partitions for the current VISTA install, with Users and Program Data on a different partition that the operating system. The current partition scheme will re-organized and simplified.

  • If you suggest to do it during the Windows-7 Custom clean install, will I still be able to modify this drive partitions scheme (using the Disk Option Advanced mode) in the same custom install session?

  • Since the external drive is operating in IDE Mode with the ICH10R controller, what is the implication that it has no hotplugging capability? I can not see where itI can be stopped in the status bar? Is it safe to power it off when the system is running?

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marked as duplicate by Oliver Salzburg Oct 15 '13 at 21:29

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 10 down vote accepted

Upgrade to Windows 7 first (as it supports newer hardware).

Then 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 this you’ll have to restart your computer, go to BIOS and enable AHCI. When you log in to Windows again, you’ll notice the installation of drivers for AHCI. Another restart will be required to finish the driver installation.

Source: MSKB

you should also check the motherboard manufacturer's website for the latest controller driver.

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Thanks for the link and instruction. I did come across this too but dismissed sine I did not notice the error message this solution is fixing. There might be one when a display (blue) blinked at the end of an attempted boot-up when Windows restarted itself. If I understand correctly I could try this under vista too. – Donat Jan 11 '10 at 20:32
It worked like a breeze on Vista 64Bit. I did the simple registry change. I copied the files from BootDrv\iMSM\64Bit folder in the Gigabyte install CD onto a usb stick. And after two reboot, voila. Thanks – Donat Jan 12 '10 at 7:28

I'm surprised switching from IDE to ACHI prevented you from booting. If you have many hard drives, the order of partitions could change and cause vista not to boot if the "first" ACHI drive happens to be different from the "first" IDE drive. Have you can tried to readjust the drive order in your BIOS until you find the right one?

Whatever you do, when you are ready for your clean install, just reboot, change to AHCI, and pop in the windows 7 DVD. The rest will be history.

If you actually manage to log in vista with AHCI, know that you can do a clean windows 7 install from within vista if you wish. Just copy the DVD/ISO content to an empty folder on an extra partition and start the setup from there. Do not choose upgrade, instead pick the custom install. Now I have only tried it by selecting another, empty partition. If you pick your current vista OS partition, I am not sure what the behavior is.

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Hi, I have only one internal harddrive, the CD-DVD drive is an old drive I recycled and isn't a SATA device. The external SATA drive was not powered when I tried. Also, when I changed the mode in Bios, the system would start booting and then restart automatically - it seems VISTA was booting. I'll check again. Thanks for the suggestion. – Donat Jan 11 '10 at 18:31
It was not the issue. I follow the instruction below to swicth to AHCI Mode and update the drivers for Vista. For the Windows 7 clean install I'll have the latest driver handy too, but at least I'll be in the right mode. Thanks. – Donat Jan 12 '10 at 7:32

Considering your other question regarding upgrade versus clean install, I'd go with a full backup of your files and a clean Windows 7 install. Then you can worry about having full control over AHCI.

If you do an upgrade, you might be able to cheat by enabling AHCI in Vista before the upgrade, but I don't know enough to know that this will work.

Theoretically, knowing how the upgrade works (it effectively makes a copy of your personalised data and installed programs and settings, installs a clean version of Windows 7, and then applies said personalisation, programs and settings), it may actually work.

But that's what full system backups are for! :-)

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I was able to easily change to AHCI mode in Vista and will start on the right foot for the custom clean install of Windows 7. Thanks. – Donat Jan 12 '10 at 7:33
That's good to know. It's a lot easier than figuring out how to enable SMP support in XP after installation :-) – user3463 Jan 12 '10 at 8:30

I would recommend doing a full backup of your Vista files and doing a clean install of Windows 7. If you choose this route make sure you change the disk configuration from IDE to AHCI in your BIOS before beginning the Windows 7 install.

When you begin the Windows install, you have 2 choices with regards to the AHCI drivers:

  1. Go to your motherboard's website and download the "F6" AHCI drivers and copy it to a USB stick or a floppy (if you are still using those). During the initial Win 7 install, you can point to the AHCI drivers on this USB stick/floppy so they canl be installed.

  2. Just let Microsoft install the default AHCI drivers but be sure to upgrade them after the Windows 7 install completes. Usually the motherboard manufacturer will have a version of Intel's Matrix Storage drivers (for RAID and AHCI) on their website for download. If you forget to upgrade the drivers you might find that your internal Hard Drives are being treated like external drives which are removable.

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Will Windows 7, when beginning to install, be able to read/access the drive and validate that there is a previous version of Windows to activate after changing mode from IDE to ACHI? – Donat Jan 11 '10 at 20:13
I first used the drivers from the motherboard CD. After the first install was complete I downloaded from Intel the latest AHCI Intel storage matrix drivers too. Thanks. – Donat Jan 12 '10 at 7:30

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