AHCI : Enable in Windows 7 / Vista

AHCI : Enable in Vista and Windows 7 after OS install​

   Information

AHCI Advanced Host Controller Interface makes NCQ Native Command Queing along with hot-plugging or hot swapping through SATA Serial-ATA host controllers possible; Vista was the first to offer this feature. The issue with AHCI is it needs to be enabled in the BIOS prior to OS installation; doing so after you have installed the OS will disable the PC. The reason why is Windows disables the AHCI drivers not needed durring installation.

This tutorial will show you how to enable AHCI after you have installed the OS if you didn't already have AHCI enable in the BIOS when you installed the OS.

   Warning

Changing values in the Windows registry can disable your machine; if you're not sure how to do this please post a question in this tutorial and someone will be glad to help you.

   Note

This method will also work for Windows Vista though the default DWORD string value in Vista will be "4" where it will be "3" in Windows 7.

As a precaution it would be a good idea to create a "System Restore Point" before you start this, the tutorial can be found at the link below.

System Restore Point - Create

Let's get started!
1) In the Windows start menu search box type regedit, right click the entry, click Run as Administrator, enter your user credentials for the UAC prompt, then click yes to open regedit.



2) In regedit navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services.

3) In the left pane, click on msahci, in the right pane double click on Start to modify it.


4) In the window that opens change the value to 0 (zero), and click OK.

5) In the left pane, click on iaStorV (if there), in the right pane double click on Start to modify it. Repeat step 4, and go to step 6 below.
NOTE: From: Error message occurs after you change the SATA mode of the boot drive

6) Close Registry Editor.
7) Now you'll need to restart the PC and go into the BIOS and enable AHCI. When Windows boots up, it will finish installing the AHCI drivers.



8) You will need one final restart to finish the process after the drivers are installed.

   Note

For those with nForce boards, have a look at the Information post below.

The method was worked out by Everlong and credit for that goes to him, thanks mate!

Enjoy!

Related Tutorials

---

• How to Enable AHCI in Windows 8 and Windows 10 after Installation
• How to Enable HIPM and DIPM for your SSD and HDD in Windows 7

 

[ZaLiTH]

The HTPC is pretty simple. Currently only 1 HDD and 1 DVD drive. Both are SATA. Once I have this working I have a second driver to add for dedicated HTPC recording space.

If they're both SATA drives, then I'm sorry to say it, but I'm out of ideas... I've gone through everything that gave me trouble when I changed my system to use AHCI, and still no luck. Sorry about that..

And my apologies for not replying yesterday, I don't have internet at home, so I reply to posts while I'm at work.

 

[SJMaye]

The HTPC is pretty simple. Currently only 1 HDD and 1 DVD drive. Both are SATA. Once I have this working I have a second driver to add for dedicated HTPC recording space.

If they're both SATA drives, then I'm sorry to say it, but I'm out of ideas... I've gone through everything that gave me trouble when I changed my system to use AHCI, and still no luck. Sorry about that..

And my apologies for not replying yesterday, I don't have internet at home, so I reply to posts while I'm at work.

I called the motherboard manufacturer. This board is a Gigabute GA-965P-DS3 Rev. 3.3 with an Intel chipset ICH8. They informed me there is no driver for this chipset to work with Windows 7. They said my board is so old they don't have one to even test a driver for this chipset if they had one.

Driver for a motherboard chipset? Now we are getting in to territory I know nothing about. For whatever reason the issues I was having causing me to want to go to AHCI have gone away. I am not comfortable not knowing why, but for now I will leave well enough alone.

I just wanted to write back to you guys to thank you for all the help and to let others know if they run in to the same thing.

 

[Bare Foot Kid]

Hello SJMaye, thanks for the feedback; just remember we're always here if you have need.

 

[Spidey1976]

Remember to post back so we know how it sorts out.

Spent the last 12 hours or so preparing for the fresh install by moving pix, music, and videos to DVD (I know... I should get an external HDD - had bad experience so far though) - my old 4x DVD-R's burned at 3.9x and took about 15-20 min each - my other 16x DVD-R's did the job in 5 minutes, so I believe the SATA fix is operational

 

[Spidey1976]

Hello Spidey1976.



If you will have NO DATA on the HDD that you want to save have a look at this tutorial at the link below, it'll show you how to do a secure erase while you do a clean install; you're right enable AHCI in the BIOS first and you won't have to mess around with the registry at all; be sure and keep me informed.


This works for HDDs also.

SSD : Optimize for Windows Re-Installation

Forgot to ask... I will be using an upgrade disk only... will this still work, or does the install look for something left behind to work properly?

 

[Bare Foot Kid]

Hello Spidey1976.



As soon as you get to the "install" screen press shift+F10 to get to a command window.



Also have a look at the tutorial at the link below.

How to Do a Clean Install with a Upgrade Windows 7 Version

 

[shanouser]

Ok, I did change the 3 keys - Msahci, IAstor, IAstorV 'start' value to 0, but after restarting and enabling the AHCI mode from BIOS, I still got the BSOD with 000007b error.
The system is Dell Latitude D830 laptop with ICH8M chipset.
Any ideas?

 

[Bare Foot Kid]

Hello shanouser, welcome to Seven Forums!




Why are you changing "the 3 keys - Msahci, IAstor, IAstorV 'start' value to 0" when this tutorial only asks to change the value of the "msahci" key and no other value, where did you get that information?

 

[shanouser]

From here:
Error message when you start a Windows 7 or Windows Vista-based computer after you change the SATA mode of the boot drive: "STOP 0x0000007B INACCESSABLE_BOOT_DEVICE"

Any ideas why AHCI can not be enabled using value = 0 for the MSAHCI and/or IASTOR keys in the registry?

 

[Bare Foot Kid]

Yes, put everything back to the original settings and change just change the value of the msahci key, doing a system restore to a point before you made the changes will restore the original values.


How to Do a System Restore in Windows 7

 

[shanouser]

Still no luck.
Changing the msahci key value to 0 does NOT fix the issue.
I still get BSOD with 0x0000007B INACCESSABLE_BOOT_DEVICE error when I enable the AHCI mode from the BIOS.
Any other ideas?

 

[Bare Foot Kid]

Are you using an NVidia nForce main-board?

 

[shanouser]

As stated before: Intel ICH8M mobile chipset on Dell Latitude D830 laptop.

 

[Bare Foot Kid]

As stated before: Intel ICH8M mobile chipset on Dell Latitude D830 laptop.

Sorry mate, you did, didn't you; I'm fresh out of ideas, keep checking back though as someone may come up with a solution for you at any time.

Have you communicated with Dell?

 

[Dave76]

Ok, I did change the 3 keys - Msahci, IAstor, IAstorV 'start' value to 0, but after restarting and enabling the AHCI mode from BIOS, I still got the BSOD with 000007b error.
The system is Dell Latitude D830 laptop with ICH8M chipset.
Any ideas?

Still no luck.
Changing the msahci key value to 0 does NOT fix the issue.
I still get BSOD with 0x0000007B INACCESSABLE_BOOT_DEVICE error when I enable the AHCI mode from the BIOS.
Any other ideas?

As stated before: Intel ICH8M mobile chipset on Dell Latitude D830 laptop.

Hi shanouser,

Did you follow the tutorial exactly?
There is an additional re-boot at the end, also try another re-boot to confirm that the driver installed.

Be sure to make an image backup of everything before trying to change the registry and loading the AHCI driver. The other alternative is to be prepared to do a clean install, if you have to do it this way, set your bios to AHCI before the install.

Next option is to D/L the latest AHCI driver from Dell for your laptop, make the registry change, install the Dell driver, then continue with step #4. Be sure to do the extra re-boot.

Another option is to D/L the ICH8M driver from Intel, be sure to get the correct driver. Continue as above with Step #4.

If you still have trouble, check the Dell site for an updated BIOS for your Latitude D830. Be aware of the possible problems when updating your BIOS, the worst case is bricking your laptop.
Then try again with the Dell driver and Intel driver as mentioned above.

I did manage to change my Dell desktop and S17 laptop without the registry edit, by installing the new driver, when asked to re-boot, immediately go to the BIOS and change to AHCI, start normally, re-boot again. This may work for you, but if it didn't work with the registry edit then it likely won't.

Let us know if you get it changed, or have any questions.

 

[Buggsy2]

Just found this tutorial...

Just found this and have a question, what about a computer which BIOS does not have the AHCI option?

 

[Bare Foot Kid]

Just found this and have a question, what about a computer which BIOS does not have the AHCI option?

Hello Buggsy2, welcome to Seven Forums!


In that case it's not possible to enable AHCI for that PC.

 

[Mulaka]

   Information

Just to put in here for nForce users, nForce boards do not support AHCI (with the exception of nForce boards that include onboard graphic cards), and also don't send the TRIM command for SSDs. It can do NCQ through its controller though. The JMicron SATA ports do support AHCI, but you'd get worse performance running a HDD through these, than on the normal SATA ports.

You can uninstall the Nvidia controller though in Device Manager and install Microsoft's IDE Controller, which can send TRIM commands for SSDs.

Head to Device Manager (Open Start menu, type Device Manager), and click "IDE ATA/ATAPI Controllers", and you will see 3 Nvidia Serial ATA Controllers. Right click one of them and click "Properties" and go to the "Driver" tab. Click "Update Driver". Click "Browse my Computer", and then "Let me pick". You will see the option to choose "Standard Dual Channel PCI IDE Controller". Click this and click "Next" and let it install.

Do the same for the other two Nvidia Controllers in Device Manager and restart your system. After the controllers have installed, you will be asked to reboot again.

SSDs will now have a slight performance boost with the TRIM command, and also regular HDDs also have a slight increase as well.

I have an nForce board; the 650i. Problem is, when I go to device manager, there are no nVidia sections under IDE ATA/ATAPI Controllers. They are under Storage Controllers! Look at my screenshot! How can I correct this?

 

[Everlong]

Try installing the latest nForce drivers first from the Nvidia website. This will install the Nvidia Storage Controllers for you

 

[IntelliMoo]

I have an nForce board; the 650i. Problem is, when I go to device manager, there are no nVidia sections under IDE ATA/ATAPI Controllers. They are under Storage Controllers! Look at my screenshot! How can I correct this?

That is actually normal for the nvidia sata performance driver (10.x) included with windows. Once you install the one (11.x) from the latest nforce package, it will then be in the proper device section, and enable command queuing (NCQ).