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

 

[Brink]

step 3 ... cilck "Exit"

note, the click is mispelled. great tutorial, though.

Thank you TsunamiZ. Corrected.

 

[chamjiee]

hi
i have dual boot setup .. windows 7 ultimate x64 with server 2012 r2 preview
now i hvae done all as mentioned above in windows 7.. and successfully booted into win 7 machine . and it installed drivers ..

now before booting into server 2012r2 .. i read an article about ahci on wiki wiki which says

On Windows 8 and Windows Server 2012, the name of the controller has changed from msahci to storahci,[4] and the procedure to upgrade to the new controller to it is similar to that of Windows 7.[5] On Windows 8 and Windows Server 2012, changing the SATA mode to AHCI without updating the registry will make the boot drive inaccessible.

so i went to bios changed back to what it used to be earlier adn booted into srever2012 r2 .. and wanted to change it accordingly .. but it is giving me the value of 0 in start variable .? what should i do ?


thanks

 

[DocDJ]

From all the above discussion, it appears that you can enable AHCI, post-install, and get some benefit from existing SATA drives. Do I *HAVE* to set AHCI on for my drives on the boot following the change to the registry, or can I wait for another re-boot? (I like to do things in small increments to make backout easier.)

 

[Brink]

Hello DocDJ,

It would be best to set AHCI right after making the registry change to avoid any potential issues.

 

[chamjiee]

bump please someone answer post #521

 

[Brink]

hi
i have dual boot setup .. windows 7 ultimate x64 with server 2012 r2 preview
now i hvae done all as mentioned above in windows 7.. and successfully booted into win 7 machine . and it installed drivers ..

now before booting into server 2012r2 .. i read an article about ahci on wiki wiki which says

On Windows 8 and Windows Server 2012, the name of the controller has changed from msahci to storahci,[4] and the procedure to upgrade to the new controller to it is similar to that of Windows 7.[5] On Windows 8 and Windows Server 2012, changing the SATA mode to AHCI without updating the registry will make the boot drive inaccessible.

so i went to bios changed back to what it used to be earlier adn booted into srever2012 r2 .. and wanted to change it accordingly .. but it is giving me the value of 0 in start variable .? what should i do ?


thanks

bump please someone answer post #521

Hello Chamjiee,

Sorry for the late reply.

With "Start" set to 0 in the registry of Windows Server 2012, you should be able to boot into Windows Server 2012 with AHCI set in BIOS.

Were you having an issue with Windows Server 2012 not booting with AHCI?

If for some reason Windows Server 2012 doesn't boot, then you could just boot back into your BIOS to set it back to what you had before AHCI to be able to again.

 

[chamjiee]

hi
i have dual boot setup .. windows 7 ultimate x64 with server 2012 r2 preview
now i hvae done all as mentioned above in windows 7.. and successfully booted into win 7 machine . and it installed drivers ..

now before booting into server 2012r2 .. i read an article about ahci on wiki wiki which says

On Windows 8 and Windows Server 2012, the name of the controller has changed from msahci to storahci,[4] and the procedure to upgrade to the new controller to it is similar to that of Windows 7.[5] On Windows 8 and Windows Server 2012, changing the SATA mode to AHCI without updating the registry will make the boot drive inaccessible.

so i went to bios changed back to what it used to be earlier adn booted into srever2012 r2 .. and wanted to change it accordingly .. but it is giving me the value of 0 in start variable .? what should i do ?


thanks

bump please someone answer post #521

Hello Chamjiee,

Sorry for the late reply.

With "Start" set to 0 in the registry of Windows Server 2012, you should be able to boot into Windows Server 2012 with AHCI set in BIOS.

Were you having an issue with Windows Server 2012 not booting with AHCI?

If for some reason Windows Server 2012 doesn't boot, then you could just boot back into your BIOS to set it back to what you had before AHCI to be able to again.

thanks for your kind reply . i havent yet tried booting int server 2012 r2 after setting to ahci in bios.. every time i need to boot into server i reset the setting autodetct raid and when i want to logon to 7 i again reset it ..

quite pesky
thanks will report after i boot into srever

 

[DocDJ]

Hello DocDJ,

It would be best to set AHCI right after making the registry change to avoid any potential issues.

I was just about to make the registry change and decided to backup a few files to my IDE CDROM. Seems my IDE port just died (tried new drive & connectors, no go). So replaced it with a SATA DVD drive.

Before I make the AHCI change, I want to know if this will affect the SATA DVD or if the SATA DVD will affect the AHCI setting.

You're not paranoid if they really are out to get you!

 

[chamjiee]

hi
i have dual boot setup .. windows 7 ultimate x64 with server 2012 r2 preview
now i hvae done all as mentioned above in windows 7.. and successfully booted into win 7 machine . and it installed drivers ..

now before booting into server 2012r2 .. i read an article about ahci on wiki wiki which says

On Windows 8 and Windows Server 2012, the name of the controller has changed from msahci to storahci,[4] and the procedure to upgrade to the new controller to it is similar to that of Windows 7.[5] On Windows 8 and Windows Server 2012, changing the SATA mode to AHCI without updating the registry will make the boot drive inaccessible.

so i went to bios changed back to what it used to be earlier adn booted into srever2012 r2 .. and wanted to change it accordingly .. but it is giving me the value of 0 in start variable .? what should i do ?


thanks

bump please someone answer post #521

Hello Chamjiee,

Sorry for the late reply.

With "Start" set to 0 in the registry of Windows Server 2012, you should be able to boot into Windows Server 2012 with AHCI set in BIOS.

Were you having an issue with Windows Server 2012 not booting with AHCI?

If for some reason Windows Server 2012 doesn't boot, then you could just boot back into your BIOS to set it back to what you had before AHCI to be able to again.

hi

With "Start" set to 0 in the registry of Windows Server 2012 R2, you should be able to boot into Windows Server 2012 with AHCI set in BIOS.

i was not able to boot into server 2012r2 .. :huh:

what should i do ..
i am posting it from server 2012r2 after defaulted back the ahci settings to what those were earlir ..

i am stuck in going to bios and setting the vale appropriatly each time i log on ..

haaaaaaaaaalp :devil:

 

[Brink]

Chamjiee,

You might just convert Windows 7 back to what you had before that allows you to boot either one without changing this setting.

If you should ever need to reinstall both OSs, then set BIOS to AHCI before installing to have them both using AHCI/SATA afterwards.

 

[Brink]

Hello DocDJ,

It would be best to set AHCI right after making the registry change to avoid any potential issues.

I was just about to make the registry change and decided to backup a few files to my IDE CDROM. Seems my IDE port just died (tried new drive & connectors, no go). So replaced it with a SATA DVD drive.

Before I make the AHCI change, I want to know if this will affect the SATA DVD or if the SATA DVD will affect the AHCI setting.

You're not paranoid if they really are out to get you!

If you switch to AHCI, then you you'll need to disconnect your IDE CDROM, and just use the SATA ones instead to avoid conflict issues. Especially since your IDE is dead anyways.

The Advanced Host Controller Interface (AHCI) is a technical standard defined by Intel that specifies the operation of Serial ATA (SATA) host bus adapters in a non-implementation-specific manner. AHCI is used for SATA, so there would be no issues there.

 

[DocDJ]

Hello DocDJ,

It would be best to set AHCI right after making the registry change to avoid any potential issues.

I was just about to make the registry change and decided to backup a few files to my IDE CDROM. Seems my IDE port just died (tried new drive & connectors, no go). So replaced it with a SATA DVD drive.

Before I make the AHCI change, I want to know if this will affect the SATA DVD or if the SATA DVD will affect the AHCI setting.

You're not paranoid if they really are out to get you!

Brink: I finally got my SATA DVD drive installed and running OK. I took the plunge and followed the instructions posted here (set AHCI in Win 7, boot, THEN set it in BIOS, boot again, drivers got installed, reboot required) and it worked perfectly!

Thanks to all you dedicated folks who post the right answers and have the patience to deal with those of us who don't know all about WIN x and all the hardware details.

 

[Brink]

You're most welcome DocDJ. I'm glad we could help.

 

[chamjiee]

Chamjiee,

You might just convert Windows 7 back to what you had before that allows you to boot either one without changing this setting.

If you should ever need to reinstall both OSs, then set BIOS to AHCI before installing to have them both using AHCI/SATA afterwards.

Now that I have converted windows 7 to ahci its running very fine.

So its pointless to convert back.

Now isn't there any option to convert windows server 2012r2 to ahci?

 

[Brink]

Chamjiee,

I found this for Windows Server 2012 R2 to AHCI.

How To: Windows Home Server v1 in AHCI mode on a HP Microserver - HP Microserver - HomeServerShow Forums

 

[chamjiee]

Chamjiee,

I found this for Windows Server 2012 R2 to AHCI.

How To: Windows Home Server v1 in AHCI mode on a HP Microserver - HP Microserver - HomeServerShow Forums

I cannot understand what that thread recommends. Besides my system is dell optiplex 755

Also for the time being it is safe to say that windiws server 2012r2 if installed in auto detect legacy mode cannot be changed to ahci. Unlike windows 7

 

[Brink]

Chamjiee,

It doesn't matter about what system you have versus the one in the link. Instead it outlines how they got Windows Server 2012 R2 to boot with AHCI that may work for you as well.

 

[chamjiee]

Chamjiee,

It doesn't matter about what system you have versus the one in the link. Instead it outlines how they got Windows Server 2012 R2 to boot with AHCI that may work for you as well.

that is very cryptic to me .. i cannot understand that

I found instruction here http://forums.overcl....php?p=13183786

The issue with installing WHS version 1 on the HP Microserver N40L is that the BIOS must be in IDE mode or the server will continously reboot if you set it to AHCI.

The trick is to do the install normally. Once that's all done (patches and updates) remove the drive from the 1st slot of the drive cage and temporarily attach it to the sata connector on the motherboard that would be used to add a DVD drive.

Now reboot and go into the BIOS to change it to AHCI mode. Don't have any other pooled drives attached for convience. Now the server will boot normally, not continously reboot. You should get a message saying that their is a new device. Now you have to add the AHCI drivers, follow the link above and extract the files and install the driver.

Power down the server. Move the drive back to slot 1 of the cage, leave the BIOS in AHCI, it should now run properly. You will get some warnings because your missing your pooled drives, add the drives one at a time so the server can discover them, when your all done, do a reboot to clear any errors.

You should be golden

what the bold part means ? what he means to say that the " The trick is to do the install normally" ? what is normal mode ?
my system has no ide ports/connectors/slots.
its all sata..
and when i installedf winserver 2012r2 it was in legecy mode..


now that i changed it to ahci it keeps on rebooting.

 

[Brink]

Chamjiee,

I'm afraid that I do not have enough experience with Windows Server 2012 R2 to better help.

Personally, I'd change it back to what you had before to avoid it rebooting. Otherwise, you may need to reinstall Windows Server 2012 R2 with AHCI selected in BIOS first to have it AHCI.

 

[chamjiee]

Chamjiee,

I'm afraid that I do not have enough experience with Windows Server 2012 R2 to better help.

Personally, I'd change it back to what you had before to avoid it rebooting. Otherwise, you may need to reinstall Windows Server 2012 R2 with AHCI selected in BIOS first to have it AHCI.

I think I will have to do so. Until then hope op mentions these caveats