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How to Enable AHCI in WinXP


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  • Corsair Employees

Microsoft KB 922976



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:


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.

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  • 2 weeks later...

Hey RAM Guy,


The MSACHI service doesn't appear to be available in the same place on WinXP embedded. Any ideas where it might be?


Or do I need to install some AHCI drivers before the service is available?


I guess a more core question to my problem is what type of performance boost would I see using AHCI over IDE?


My application is a data recorder that runs on the XP embedded OS and uses SATA data drives. I have three Corsair disks for evaluation. Two of which are X256 models and one P256. We were hoping that the internal garbage collector of the P256 would at least reduce the need to periodically securely erase the disks as these will be embedded on customer aircraft. The X256 models are working as advertised with the expected write speed degradation over time, but the P256 drive is significantly slower than advertised. The ATTO benchmark for the P256 is around 50MBps (1MB writes), while the X256 is writing at 179MBps. I securely erased the drive the same way I have been for the X256 drives using PartedMagic, but the P256 doesn't perform beyond the 50MBps. I already RMA'd the first P256 drive I received because it was doing this very thing, but could the IDE/AHCI be the root cause of the poor performance of the P256 while the X256 is working fine with IDE?


Thanks in advance :)

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Anyone know if this trick works in Win 7? I just built a new machine and used the Corsair R60 SSD for my boot drive. I clearly didn't complete the build correctly because my BIOS shows the drive running in IDE mode. Actual read/write speeds are pretty good, but because my board is not running AHCI I can't utilize my eSata ports. I'd hate to start from scratch, which is why I'm on this board asking if this trick might work in Win7. Thanks in advance!
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  • 3 weeks later...
  • 9 months later...



is this correct? As far as i know, WinXP does not support msahci.sys. You can run iastor.sys from the Intel driver, but not msahci.sys.


The link in the first post is only for Vista/Win7.


Maybe i'm wrong, but




does not exist in WinXP.

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  • 3 weeks later...

For Windows XP:


1. Extract the iata_enu.exe from the latest Intel Matrix Storage drivers.

2. Switch your bios to NON AHCI mode..

3. Boot windows and go to "Device Manager"/

4. Select your INTEL ICH8 SERIAL ATA STORAGE CONTROLLER 2850 (or whatever it is on your system) and click Update Driver

5. Have Disk and select the inf file from the Matrix Storage.

6. Select the proper AHCI driver for the same chipset (in my case ICH8R).

7. Reboot and IMMEDIATELY GO TO BIOS AND CHANGE TO AHCI (elsewhere Windows will revert back easily).

8. Enjoy AHCI in Windows XP

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  • 2 months later...
  • 9 months later...

I recently tried to switch from IDE to AHCI on my WinXP PC.


I found under the BIOS of my Asus M4A89GTD motherboard that the SATA ports could be switched in 2 groups. The BIOS help screen says it's to allow DVDs to remain on IDE while hard disks can be switched to AHCI.


This made turning on AHCI much less complicated.

1) go to BIOS and enable AHCI for all SATA channels

2) set channels 5&6 back to IDE

3) Switch off and reconnect the SATA hard disk to channel 5 or 6 (the IDE channels) if it isn't already.

4) reboot to WinXP and it will find new (AHCI) hardware and install the drivers (if you have them handy)

5) switch off and connect the hard drive to one of the AHCI channels and optionally set the 2 IDE channels back to AHCI


The PC will now boot to WinXP with the hard drives using AHCI


So, if you need to switch to AHCI, it's worth checking if your BIOS can do something similar as it's a lot less hassle than other methods described here.



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  • 1 year later...


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