Home > Computing > Change SATA mode from IRRT to AHCI

Change SATA mode from IRRT to AHCI

So I got a new laptop for work. It’s a Dell E6510. First thing I did was to replace the hard drive with a Momentus XT hybrid drive. It would have been nice to go with an SSD but to get the amount of storage I need would have cost too much. Next was a clean install of Windows 7 64bit along with all the applications, sysadmin tools, development tools, etc… The one thing I forgot to do was to verify all the bios settings. When I got around to that I noticed that the SATA was set to RAID. This is for the Intel IRRT which allows you to connect an external drive and have it configured as RAID 1 for a rapid restore if your hard drive dies. From what I’ve read this mode tends to slow the system down a little. But this post is not to discuss the pros and cons of IRRT.

So I go into the bios and change it to AHCI. Of course nothing is ever easy and I got a BSOD. After much searching I found a solution and am posting here in a single location for simplicity. Links to the original articles are at the end of this post. As always use this information at your own risk and make sure you have a backup. Also make sure you have your BitLocker recovery key available.

Download the latest Dell SATA drivers. These should be the Intel Rapid Storage Technology drivers

Next follow the steps in MicroSoft KB 922976 to verify the msahci service is set to start correctly

  1. Open regedit
  2. Navigate to HKLM\System\CurrentControlSet\Services\Msahci
  3. Verify the Start key is set to 0

Next you’ll need to add a registry key for the QM57 chipset. You can copy and paste the key below into notepad and save it as a .reg file, then just double click it.

Windows Registry Editor Version 5.00


Now you restart the computer and hit F2 to get into the bios and set the SATA mode to AHCI.

NOTE: there is no need to turn off BitLocker.

When the system finishes booting up don’t tell it to restart. Run the SATA driver installer and then restart.


This is the MS KB article: http://support.microsoft.com/kb/922976

This is the original tutorial with good info but doesn’t quite work: http://forum.notebookreview.com/dell-latitude-vostro-precision/349173-tutorial-how-switch-irrt-ahci-mode-e6400-e6500-vista.html

This is the second thread with the correct registry key information for the QM57: http://forum.notebookreview.com/dell-latitude-vostro-precision/515289-switch-e6510-qm57-chipset-irrt-ahci.html

Categories: Computing Tags: , , ,
  1. bommel
    June 20, 2011 at 7:47 AM

    I wrote a tool that can automate the process of creating the necessary registry file for switching to/from AHCI mode. The tool and explanation can be downloaded on my blog: http://www.remkoweijnen.nl/blog/2011/06/18/switch-sata-operation-mode

  2. Art
    May 15, 2012 at 8:49 AM

    Thanks, I was looking to switch my 6510 to AHCI prior to swapping in an SSD and yes after switching to AHCI there was a definite improvement in performance now waiting for that SSD in the mail !

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