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

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• 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

 

[seekermeister]

Due to problems that I'm still dealing with in W7, I have not yet gotten XP reinstalled, but when I do, there is a driver for a floppy that I think is for the Marvel controller on my MB. I imagine that it include AHCI, but I won't know until I get to that point. If it is, then XP will be running ACHI, but W7 won't, because the drive that it is installed on is not capable of it. This leaves me wondering if I still need to enable AHCI in W7, so that any access/writes done from there would be utilizing AHCI properly?

 

[Eliteofdelete]

Dear Bare Foot Kid,

Background Story:
My friend recently got an 2TB external with an Esata connection but his computer kept messing up with it. So we decided to do a reformat and enable the ACHI before format like it is recommended (he was already planning a reformat, this was just an added bonus).

After setting AHCI on We got to the Windows install screen and deleted the 2 partitions (reserve and normal) and ran the format. However windows gave us an error saying:
"Windows cannot be installed to this disk. This computer's hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's BIOS menu."

We tried several things to get around it including unplugging all other hard drives from the computer and using your guide to get a clean reformat (http://www.sevenforums.com/tutorials/91339-ssd-hdd-optimize-windows-reinstallation.html). Nothing worked so we gave up and put the computer back into IDE and installed Windows 7 fine.

However, we still wanted to get AHCI working so we used this guide to try to turn it on. First, we did all the Windows updates that were popping up and downloaded and installed the latest bios and chipset for his motherboard (A780GM-A V1.1). Then we followed this guide and restarted. It got past the motherboard information but then gave a black screen stating that no OS could be found.

We then restarted and went to the bios and looked to see what it was booting from. It appeared that the hard drive was not showing up. So we went to the boot menu and found the hard drive and booted from there which found the OS and started windows fine, automatically downloading the AHCI drivers.

To make it find the hard drive to boot from, we went back to the bios and looked under the advance CMOS settings but still couldn't see what hard drive was showing up in the 1st/2nd/ect boot order. So we went to the hard drives option and set his to the first one and looked again under the boot order. It showed up so we selected it and started up windows fine.

Result:
We plug the Esata in and it instantly detects the external drive. This was not occurring before the reformat. We moved a file from the external to his desktop and it shows ~120MB/s speed and finishes in a several seconds.

Problem:
Then we tried to move a file from the desktop to the external. It reports a 400MB/s speed and the bar fills up to ~75% (it is a 600MB file) but stops. This was one of the problems that was occurring before the reformat. The file stops transferring and the computer starts to lag a bunch till it freezes completely. Hitting "cancel" causes the file transfer to sit forever attempting to cancel, with no results. Opening task manager sometimes shows multiple explorer.exe's running. All can be ended except one and the file transfer won't stop, sitting there frozen. Attempting to restart the computer results in the computer sitting on the "logging off" screen indefinitely, requiring a hard reboot. Only after restarting, which takes 1-2 mins longer than normal, can we do anything on windows again.

Do you have any idea what my be causing the file to be unable to transfer to the external? We also tried mine which is the exact same as yours and the same problem. Mine also worked fine on my computer with Esata. Now we are about to try finding AHCI drivers specific for his motherboard and see if that fixes the problem.

 

[Solarstarshines]

I ,used this earlier via Essenbe and I have to say this is a awesome tool

Barefoot kid you are a Genius no doubt .....+1

 

[Bare Foot Kid]

Do you have any idea what my be causing the file to be unable to transfer to the external? We also tried mine which is the exact same as yours and the same problem. Mine also worked fine on my computer with Esata. Now we are about to try finding AHCI drivers specific for his motherboard and see if that fixes the problem.

Hello Eliteofdelete, welcome to Seven Forums!

Unfortunately I have no suggestions for you, it could be any number of things, to include an issue with the file itself and I have no way to pin it down, I doubt seriously it's the AHCI drivers; I would be curious though if you find the issue.

I ,used this earlier via Essenbe and I have to say this is a awesome tool

Barefoot kid you are a Genius no doubt .....+1

Hello Tommy, I'm pleased it was a help to you and thank you for the kind words.

 

[Eliteofdelete]

Thanks Bare Foot Kid,

Sadly, I do not think we will be finding the problem. Updating the drivers only fixed it to show the correct transfer speed but it still froze at the ~75%. The restarting while the transfer was frozen was creating corrupted files that couldn't be deleted so we had to do a disk repair which thankfully fixed it.

I know it isn't the file being transferred as it does it for everything going to the external with Esata. We have decided we will just be using USB to put files onto it and Esata to take them off.

Thanks for all your help tho, your guides are amazing.

 

[Bare Foot Kid]

Thanks Bare Foot Kid,

Sadly, I do not think we will be finding the problem. Updating the drivers only fixed it to show the correct transfer speed but it still froze at the ~75%. The restarting while the transfer was frozen was creating corrupted files which couldn't be deleted so we had to do a disk repair which thankfully fixed it.

I know it isn't the file being transferred as it does it for everything going to the external with Esata. We have decided we will just be using USB to put files onto it and Esata.

Thanks for all your help tho, your guides are amazing.

Hello again, too bad mate but if you find the issue be sure to post back here with an update and thank you for the kind words my friend.

 

[SJMaye]

I tried this once before a while back only to find out my bios did not support AHCI. I have since replaced that motherboard and know the new bios does support AHCI.

Before I try this I wanted to ask if my 3 SATA drives must also be compatible. And, if so, how I can find out easily?

 

[ZaLiTH]

I tried this once before a while back only to find out my bios did not support AHCI. I have since replaced that motherboard and know the new bios does support AHCI.

Before I try this I wanted to ask if my 3 SATA drives must also be compatible. And, if so, how I can find out easily?

Being SATA drives, they will be compatible. As per the AHCI Wiki page:

The Advanced Host Controller Interface (AHCI) is a technical standard defined by the Intel Corporation that specifies the operation of Serial ATA (SATA) host bus adapters in a non-implementation-specific manner.

Essentially that it means the 'compatibility' side of AHCI comes from how the 'SATA Controller' accessed the SATA drives. The drives will still spin up and read / write as instructed, but they will simply be instructed differently by the controller.

 

[SJMaye]

Thank you ZaLiTH.

I read the same things, but wanted to be sure. I will give it a shot.

 

[dwarfer66]

Ok, I knew I'd have a hiccup attempting this. During install of my OS a few weeks ago I tried to enable AHCI but kept failing boot so I just stuck with IDE and all has been working well. Figured why not give it a try now that everything is running smoothly. I added a restore point, modded the reg then enabled AHCI in the bios. Upon reboot BIOS starts listing the HD's then as the rest of that particular page is rendering I notice the primary drive listing disappears. Towards the end of BIOS initialization I'm greeted with a notification that no OS is available to boot.

After double checking that I hadn't inadvertently change something I shoulden't have in the BIOS I decided to do a "System Restore" via "System Recovery" off the retail disk. Unfortunately when I get to the System Recovery's option of choosing which OS the apply the restore point to I have no OS to choose from. For some reason it's not detected.

Any suggestions?

Hey mate that happened to me too, a few weeks ago, I found out the problem was the option UNDER the option to enable AHCI was causing the operating system to not be recognized, I didnt realize that until I did a new install! Not really game to try it again!.

 

[SJMaye]

Only in my World!

Everything went like the instructions, but for whatever other reason a video issue cropped up. This is an HTPC. I did the REGEDIT change no problem. Did a restart and hit Delete key to enter bios and screen went blank. No image. I know it is unrelated to the registry change, but you can see this could pose a problem.

I tried both DVI (with DVI to HDMI adapter) and HDMI ports on the ATI 5970 card using HDMI to TV, but neither would produce a picture. I finally powered down and installed my desktop monitor with DVI connection. Everything worked fine now. Go figure. I went in and changed the bios to AHCI and rebooted. Installed drivers and everything looked good. I disconnected the monitor and reconnected the TV. No picture. again trying all ports. Nothing. Finally reconnected the monitor and it worked fine. Set bios back to IDE and did a system restore to get WIndows back to where it was before the change. Reconnected TV, rebooted and all is good only no AHCI.

I realize there should be no connection between the AHCI and the video issue, but can someone point me in the right direction? This makes no sense to me.

 

[james cullen]

Thanks BFK, great tutorial, my computer has had a real boost in performance.

One thing you may be able to help out with though and it's a problem I have in device manager, seems there is a problem with ATA Channel controllers, it doesn't seem to be effecting the machine though.

What do you think that might be, the warning is that the device can't start.

Cheers and thanks for the increase in performance.

James

 

[ZaLiTH]

Thanks BFK, great tutorial, my computer has had a real boost in performance.

One thing you may be able to help out with though and it's a problem I have in device manager, seems there is a problem with ATA Channel controllers, it doesn't seem to be effecting the machine though.

What do you think that might be, the warning is that the device can't start.

Cheers and thanks for the increase in performance.

James

You could try uninstall the device and restart your computer. Windows will try reinstall any missing drivers for devices listed here, but it won't do anything automatically for faulty drivers.

If it's a driver-related problem, that's probably the safest way to sort it out. If it requires custom device drivers, you'll be prompted for the correct driver at start up, otherwise Windows will use a driver from it's supported list.

 

[james cullen]

Thanks for your help ZaLiTH, I uninstalled those two drivers, restarted and Windows tried to install drivers but failed, now I have the warning again but this time I have lost alot of ATA channels.

 

[ZaLiTH]

Thanks for your help ZaLiTH, I uninstalled those two drivers, restarted and Windows tried to install drivers but failed, now I have the warning again but this time I have lost alot of ATA channels.

Hmmm... That is somewhat strange. I'd suggest you try re-install the drivers manually then; either use your motherboard driver CD or download the latest drivers from Gigabyte's website.

Just found a thread on Toms Hardware forum regarding AHCI on your motherboard.. While his/her original problem is different to yours, there is one post that may help you somewhat. There a few driver versions listed in this post that you may want to try. I'd say use the listed versions as a reference and try find drivers that are at least that version or newer.

I probably should have asked this first, but can you access all your drives in Windows, or are they not listed in Computer?

 

[james cullen]

thanks,

yes I can access all my drives, in fact after doing the AHCI thing and instaling the Intel istor driver my machine is screaming along, running smooth, never been better.

Just these pesky warnings.

If I reinstall the Gygabyte drivers will they wipe the new achi and Intel storage drivers or send the bios back to IDE

Cheers again thanks for your help

James

 

[ZaLiTH]

thanks,

yes I can access all my drives, in fact after doing the AHCI thing and instaling the Intel istor driver my machine is screaming along, running smooth, never been better.

Just these pesky warnings.

Ok, that's good news then. That means the warnings aren't because of a physical problem (such as faulty hardware or loose connections), it'll be software-related.

If I reinstall the Gygabyte drivers will they wipe the new achi and Intel storage drivers or send the bios back to IDE

Cheers again thanks for your help

James

When drivers are installed to Windows, they're kept in the driver cache even if new drivers are installed, only one driver can be active and assigned to hardware at a time though.

By installing the drivers from Gigabyte, it will assign those drivers to the ATA controller instead of the driver being used currently (in your case, the Intel drivers).

So if, for example, the drivers from Gigabyte don't contain a driver for device XYZ, and you have an Intel driver currently installed for device XYZ, then that will stay there after installing the Gigabyte driver pack.

It won't change anything in your BIOS though, that's completely separate. Think of it this way: the options you set in the BIOS determin how Windows detects the hardware, while the drivers determine how Windows accesses that same hardware.

 

[james cullen]

thanks,

yes I can access all my drives, in fact after doing the AHCI thing and instaling the Intel istor driver my machine is screaming along, running smooth, never been better.

Just these pesky warnings.

Ok, that's good news then. That means the warnings aren't because of a physical problem (such as faulty hardware or loose connections), it'll be software-related.

If I reinstall the Gygabyte drivers will they wipe the new achi and Intel storage drivers or send the bios back to IDE

Cheers again thanks for your help

James

When drivers are installed to Windows, they're kept in the driver cache even if new drivers are installed, only one driver can be active and assigned to hardware at a time though.

By installing the drivers from Gigabyte, it will assign those drivers to the ATA controller instead of the driver being used currently (in your case, the Intel drivers).

So if, for example, the drivers from Gigabyte don't contain a driver for device XYZ, and you have an Intel driver currently installed for device XYZ, then that will stay there after installing the Gigabyte driver pack.

It won't change anything in your BIOS though, that's completely separate. Think of it this way: the options you set in the BIOS determin how Windows detects the hardware, while the drivers determine how Windows accesses that same hardware.

Thanks so much for your help, I updated the gigabyte drivers and the warnings have gone.

Thanks again

James

 

[Synaptic Sam]

Flawless victory! AHCI is mine.

Thank you very much.

 

[Bare Foot Kid]

Hello Sam, good you got it going.