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

 

[Dave76]

Information is hard to find, very little on Intel's site.

Here's some basic info, you probably have seen these, posted for others to see if they haven't already.

RAID From Wikipedia

Advanced Host Controller Interface (AHCI)


And the rest is really hard to find, mostly discussions a couple of benchmark tests, not much info really.
As you mentioned, I find this rather strange, even an Intel search gives old information.


Other misc info found, that might be of interest.


Benchmark Performance SSD Testing: AHCI vs IDE

 

[mendopaul]

Yes I enabled it before current format.

Can I reopen this thread? I'm not sure I can get my computer to boot if I change the BIOS to AHCI. Not understanding the problem, I've tried to change that state to AHCI and the machine would not boot. After changing it back to IDE enhanced it would then boot. But I'm eager to make this change if it will work and I've appreciated your prior postings in this thread.

 

[Bare Foot Kid]

Hello mendopaul.



If you do the steps exactly as in the tutorial you should be ok.

Have a look at this tutorial at the link below before you start this to create at least 1 restore point, and 2 would be better in case you have any issues, a system restore will set the registry back to what it was before you started; be sure to post back with any further questions you may have and to keep us informed.

How to Create a System Restore Point in Windows 7

 

[Case1]

Got er done!

Hey Ted,

Wow I figured it out! I changed the # from 3 to 0, then went into the bios and switched it from IDE to AHCI and rebooted.

Is it normal that whenever I reboot it says on one of the bootup screens:

"AHCI driver INT..." before it goes to the desktop? I know it was suppose to do it when I first made the change...just wondering I guess if it will do that every time I restart now. Just making sure I didn't mess something up.

Casey

 

[Bare Foot Kid]

Hello Casey.



Well done.

The way SSDs are constructed, they don't need to be defragged.

 

[onthemour]

So I just installed my os onto my new ssd and I did it in ide mode. my previous os was on my hdd is a raid 0 format. Can I use my ssd in achi while keep my hdd in raid 0? I have a gigibyte bios and it has 2 options for changing the ide/raid/achi not sure if both have to be on what

 

[Bare Foot Kid]

Hello onthemour, welcome to Seven Forums!



I'm not sure what you're asking; are you asking if you can dual boot both the SSD and the RAID HDDs using the Windows managed dual boot?

I don't believe that would be possible; if it was a BIOS managed dual boot it may be possible though you would have to change back and forth between AHCI_SSD and RAID_HDD using the BIOS which I feel would become tedious after a while.

I had a dual boot with XP in IDE and Windows 7 in AHCI and I had to use the BIOS to boot to either and it became more trouble than it was worth before long.

 

[onthemour]

When I set bios to raid and boot into my ssd os my hdd raid0 shows up as drive f and I can access the files on it. Which is what I want. I was wondering if I am getting ahci for my ssd? I read on forums that with raid enabled I get ahci eneabled for ssd. Is this true and if so do I get trim? It is a ocz vertex2 120gig

 

[Bare Foot Kid]

When I set bios to raid and boot into my ssd os my hdd raid0 shows up as drive f and I can access the files on it. Which is what I want. I was wondering if I am getting ahci for my ssd? I read on forums that with raid enabled I get ahci eneabled for ssd. Is this true and if so do I get trim? It is a ocz vertex2 120gig

I don't have much practical experience with RAID, so hopefully someone else will have some suggestions for you, just keep checking back.

 

[WindowsStar]

When I set bios to raid and boot into my ssd os my hdd raid0 shows up as drive f and I can access the files on it. Which is what I want. I was wondering if I am getting ahci for my ssd? I read on forums that with raid enabled I get ahci eneabled for ssd. Is this true and if so do I get trim? It is a ocz vertex2 120gig

Newer computers and newer controllers typically only have IDE and RAID. If you select RAID and do NOT create a RAID all drives are running in AHCI. -WS

 

[Bare Foot Kid]

Hello WS, thanks for the information!

 

[Dave76]

Advanced Host Controller Interface (AHCI)

Many SATA controllers offer selectable modes of operation: legacy Parallel ATA emulation, standard AHCI mode, or vendor-specific RAID. Intel recommends choosing RAID mode on their motherboards (which also enables AHCI) rather than AHCI/SATA mode for maximum flexibility, due to the issues caused when the mode is switched once an operating system has already been installed.[1] Legacy mode is a software backward-compatibility mechanism intended to allow the SATA controller to run in legacy operating systems which are not SATA-aware or where a driver does not exist to make the operating system SATA-aware.

If your BIOS is set to RAID you don't have to have any HDD/SSD in a RAID array, they will still be in AHCI mode.
If you have a RAID array the other HDD/SSD will be in AHCI mode.

 

[daisu]

hi all mem 7forum !
I have some questions : I trying convert mode IDE to mode AHCI unsuccessful
Info : my main P7p55d , HDD western 250 G santa, OS Win 7 64 bit.

step 1 :
I setup new install win 7 . In BIOS I config mode IDE to mode AHCI. the process of installation begins .. screen select install OS for partion ( Partion C (format NTFS )). error message appeared : Disk manager BIOS ( not installed ). I cacel
step 2 :
Startup in BIOS . I config defaut mode IDE . Install Win 7 success. the screen in OS . I trying :
Run : regedit. I trying oder step

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: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
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

restart mycomputer I config BIOS : convert mode IDE to mode AHCI. starup : message not detected. boot disk failer.

please help me. thank's . ( My English is not good . I hope All mem read not me )

 

[Bare Foot Kid]

Hello daisu, welcome to Seven Forums!



After you exit the Windows registry you have to restart the PC to enter the PC BIOS to set the "Storage Controller" to AHCI mode so that Windows will start and install the AHCI drivers; if you just try to restart the PC without doing this the PC will not start.

 

[daisu]

thank's reply .
I trying your support . after I config mode IDE to mode AHCI in BIOS ( Storage Controller). save + F10
my computer start : screen "black" message : " reboot and select proper boot device . not starup windows.
I see my main support onboard chip J-micron JMB363.
If I setup new Win . Do I must ?
I trying step here : convert mode IDE to AHCI. Setup new win...the screen select new partion for install OS. message : " windows canot be installed to this disk. This computers harware may not. Ensure that the disks controller is enabled in the computer's BIOS menu "

 

[Case1]

Hey gang,

It is me again. Ok, I have had AHCI mode enabled and was wondering if I can run TRIM in this mode or if I even need to if possible. Also I see that one of the benefits of running in AHCI is Native Command Queuing (NCQ). Will this make my comp faster? The reason I was wondering about TRIM is I want to do whatever to keep my SSD clean and in tip top condition.

 

[Dave76]

Did you update the firmware when you got the SSD?

Which driver are you using?
The AMD guys can correct me if I'm wrong but I don't think the AMD driver can pass the trim command, you have to use the MS driver.

 

[Golden]

HI Case,

I'm not sure about the trim stuff, but here is a link that will give you some additional tips to keeping your SSD nice and clean:

Guide * Windows 7 Ultimate Tweaks & Utilities *

Regards,
Golden

 

[Case1]

Did you update the firmware when you got the SSD?

Which driver are you using?
The AMD guys can correct me if I'm wrong but I don't think the AMD driver can pass the trim command, you have to use the MS driver.

I am not sure if I did or not...hmmm, how can I tell?

 

[Case1]

HI Case,

I'm not sure about the trim stuff, but here is a link that will give you some additional tips to keeping your SSD nice and clean:

Guide * Windows 7 Ultimate Tweaks & Utilities *

Regards,
Golden

Hi Golden,

I checked and it shows that TRIM is enabled. Is TRIM something that works automatically or do I manually have to do it?