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]

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

Thanks again

James

Awesome.. Glad I could help.

 

[mikejustis]

I used your guide when I first got my ssd and it worked. I upgraded and I installed a i7-960 today and had to do the "change the registry route" again. I did it but now after boot screens I got a message saying...
"BOOT FROM AHCI CD-ROM
DISK BOOT FAILURE"
I thought it was the boot order and it isnt. I checked all that and changed back to IDE in BIOS and default settings. I then went on an endless loop of boot up until right after the balls come together to form the windows logo then BSOD, until it goes to Windows repair to an earlier time message. After that and sweating bullets it restarts, loads all the i7-960 drivers, usb drivers and all is good. I checked in the registry and the value is still "0" even after the earlier time reset.
Any ideas??

 

[ZaLiTH]

I used your guide when I first got my ssd and it worked. I upgraded and I installed a i7-960 today and had to do the "change the registry route" again.

The registry change is only meant to be done once. It's so that Windows knows the drive controller has changed and needs to reinstall drivers. Even if you switch back from AHCI to SATA, and then back to AHCI, Windows already has the drivers installed (even if they're not currently being used) so you don't need to do it again.

I suggest you try do a system restore to before the boot problems started, preferably before you even set up AHCI, then try it again.

 

[mikejustis]

Well, that would be before I installed the new cpu and it wont let me for some reason.
I think I am just going to do a new install with the Windows 7 disk I have from my first install. What steps do I need to follow to do an upgrade or repair install? At what point does the install ask if I want to use AHCI mode b/c I do not remember it asking last time. Do I enable AHCI in BIOS then restart w/ the Windows install disk in and go from there? Sorry for all the questions and thanks for your help.

 

[Dave76]

Do I enable AHCI in BIOS then restart w/ the Windows install disk in and go from there?

Yes, with AHCI selected in your BIOS before you install Win7 you will get the drivers loaded.

How to Do a Repair Install to Fix Windows 7

How to Do a Inplace Upgrade Installation from Vista to Windows 7

 

[Lorider]

Excellent tutorial. Worked for me, weather you notice performance gains or not, its still worth it, defiantly better than IDE, and HOT SWAP is another benefit, this tutorial makes it easy if you follow the steps carefully.( Still do a backup just incase ) Thanks a lot.

 

[cabelo3d]

I followed the tutorial, after set the AHCI mode in Bios the system don't boot. I got "missing operation system" error.
The Hard Drive I'm trying to set as AHCI have 2 partitions, one for the OS and the other for files. The model is ST31000528AS.

I got another 2 Hds installed in the same PC, that I use with other OS that I only use to work, they are set to Raid0 and I use to switch from Raid0 to IDE often, I jump from "work HD" (which is Raid0 one) to "game HD" (which is the single drive with 2 partitions). Will I have a problem or something that I need to be aware of, for trying to use AHCI and switch daily to Raid to use the other OS in the same PC? Sorry for the noob question tho.

Any ideas?
Thanks

 

[Brink]

Hello Cabelo, and welcome to Seven Forums.

Often there is a RAID/AHCI setting in the BIOS instead of just AHCI, IDE, or RAID. Do you have this option to use, and what did you have it originally set to?

 

[ZaLiTH]

I followed the tutorial, after set the AHCI mode in Bios the system don't boot. I got "missing operation system" error.
The Hard Drive I'm trying to set as AHCI have 2 partitions, one for the OS and the other for files. The model is ST31000528AS.

I got another 2 Hds installed in the same PC, that I use with other OS that I only use to work, they are set to Raid0 and I use to switch from Raid0 to IDE often, I jump from "work HD" (which is Raid0 one) to "game HD" (which is the single drive with 2 partitions). Will I have a problem or something that I need to be aware of, for trying to use AHCI and switch daily to Raid to use the other OS in the same PC? Sorry for the noob question tho.

Any ideas?
Thanks

One important point to remember is boot order.. Often when changing the drive controller settings on a motherboard, the boot order changes.

On the other side, if you've already got a RAID setup, then all the features of AHCI that this tutorial aims to help people to use are already in use (most specifically, NCQ).

Unless I've missed something, I'd say if you're already using the drive controller in RAID mode, even if not all your drives are part of a RAID partition it would be better for you to leave your system as-is instead of trying to switch to AHCI.

 

[cabelo3d]

Hello Cabelo, and welcome to Seven Forums.

Often there is a RAID/AHCI setting in the BIOS instead of just AHCI, IDE, or RAID. Do you have this option to use, and what did you have it originally set to?

I followed the tutorial, after set the AHCI mode in Bios the system don't boot. I got "missing operation system" error.
The Hard Drive I'm trying to set as AHCI have 2 partitions, one for the OS and the other for files. The model is ST31000528AS.

I got another 2 Hds installed in the same PC, that I use with other OS that I only use to work, they are set to Raid0 and I use to switch from Raid0 to IDE often, I jump from "work HD" (which is Raid0 one) to "game HD" (which is the single drive with 2 partitions). Will I have a problem or something that I need to be aware of, for trying to use AHCI and switch daily to Raid to use the other OS in the same PC? Sorry for the noob question tho.

Any ideas?
Thanks

One important point to remember is boot order.. Often when changing the drive controller settings on a motherboard, the boot order changes.

On the other side, if you've already got a RAID setup, then all the features of AHCI that this tutorial aims to help people to use are already in use (most specifically, NCQ).

Unless I've missed something, I'd say if you're already using the drive controller in RAID mode, even if not all your drives are part of a RAID partition it would be better for you to leave your system as-is instead of trying to switch to AHCI.

Thanks for the warm welcome!


I got 4 hdds in total on my system and 2 different installations of windows 7.
Drive A 500gb - part of the Raid 0
Drive B 500gb - part of the Raid 0
Drive C 1tb = 2 partitions, 400mb to OS system and 600 to gaming Files.
Drive D 1tb = work project files storage

Drive A+B used in Raid 0. I use this with a install of windows 7 and only for work, like 3d applications and stuff. When this is active, I mean, when I boot into windows to work, I need to change in the Bios to RAID. Then, I'll use the OS to work and I'll have:

A+B drives (1tb) which is the C: operation system "to work"
D: partition with the "gaming operation system"
E: partition that contains the gaming files and
F: work projects files.

When I change in Bios from RAID to IDE, I'll boot to another OS, which I use only for gaming and I'll have:

C: partition with the "gaming operation system"
D: partition that contains the gaming files
E: the hard drive that in this case is the Raid one, that is unaccessible, and
F: work projects files


Sounds a bit complicated I know, I hope I could clarify things.
The Hard drive I'm trying to set as AHCI is the one that is partitioned and that I use only for gaming.


I'll try to see what is the order of the hard drives and I'll report back.


Thanks in advance.

 

[ZaLiTH]

Then, I'll use the OS to work and I'll have:

...

When I change in Bios from RAID to IDE, I'll boot to another OS, which I use only for gaming and I'll have:

...

Ah, yeah I do see what you mean now.. If that's the case, then as you currently switch between RAID and IDE modes, you would instead end up switching between RAID and AHCI.

In this case, whatever you change here shouldn't affect your work (RAID) copy of Windows, only the gaming (non-RAID) instance. Only thing that I can think might cause a problem is the boot order. Not sure if all boards do this, but on my XFX 750a, each time I changed the SATA mode on my drive controller it would either forget or simply reset my drive boot order... :/


On a slightly different note: Don't you think it would be simpler to leave the controller set to RAID mode all the time and set up a dual-boot between the two instances of Windows? That would probably make life a lot easier in the long run.

 

[cabelo3d]

Yes, definitely when I switch from Raid to IDE the order of the hard drives changes too.. I didn't thought about that tho. I'll try to boot into the gaming system now with AHCI enabled and see.

Also, I haven't used a dual boot due a lack of knowledge to set it, to be honest.

I'm using about 250mb or less in the work system and the raid has 1tb.
If I could use the raid hard drives to have a dual boot system and a partition with a gaming operation system, life really would be easy, games would run faster and plus, the drive I'm actually using as a dual partitioned drive would be used as a game storage hd.

Can you point me how can I manage to achieve that? I'm willing to try it. despite the hassle of reformat everything again.

 

[ZaLiTH]

There is a tutorial here on SevenForums that covers http://www.sevenforums.com/tutorials/8057-dual-boot-installation-windows-7-xp.html; maybe you could cover the steps to prepare for dual boot from the 'Win7 Installed First' section, then continue with the second OS installation from the 'XP Installed First' section.

Most tutorials cover dual booting two separate operating systems, but as far as the steps in one OS are concerned, you're simply installing another OS, whichever OS that is doesn't really matter (only exceptions would be different partition types for things like Linux or OSX).


Anyway, it's just gone 11pm this side of the world and I need some sleep, so I'll only be able to reply again in the morning.. If you get stuck though, there are lots of friendly helpful users around here.

 

[cabelo3d]

Thanks bro!

I'll take a look at the tutorial, take some time to decide and I'll report back.
Appreciated your help.

 

[Dave76]

Have you tried leaving your system in RAID and selecting your Boot option, usually F12 depending on your system, to select the other OS hard drive?

When you start your computer, the BIOS screen will give you an option on the bottom of the screen 'Boot Options' or 'Boot Menu' or something similar, just select/press the key indicated repeatedly until the boot option menu comes up and then select the other OS HDD.

RAID has all of the benefits of AHCI, and you don't need to have any HDDs in RAID to use it.

Try this and let us know the results.

 

[cabelo3d]

I have an Evga x58 sli micro board and pressing Esc you'll go to the hard drive selection screen. I've selected the Gaming HD with Raid set in the Bios, but it reboots the pc and once it reboots it automatically enters in the Work HD, the ones that already work as Raid.

When I set in the Bios, the disks to have a different order, the Game HD as first, Windows asks to launch a repair. So what do I need to do now? Leave windows do the repair thing?

When I set the Game HD to be the first I got a blue screen. Even put 0 instead 3 in the registry.

 

[Dave76]

When you change the registry setting from 3 to 0, then on the next boot the OS (GameHD) should d/l and install the RAID drivers.
After the first re-boot, when it loads the RAID drivers, you need to re-boot again when they finish loading.

When you get both OSs set to RAID you won't have to change the BIOS IDE/RAID setting anymore.

If you want a Dual boot option when starting your computer, then run the 'Startup Repair' 3 times, this give you the option to select the OS when you boot up.
If you want to use the F12 key during bootup to select the OS you want then don't run 'Startup Repair'.

 

[brownix]

umm i dont know much about my computer after looking into all this
i have a 2x500gb and i think its a raid
how can i be sure?
and when i went to change the number to 0 it was already 0, so wat does that mean?

 

[Dave76]

If the registry is already set to 0, then you are in AHCI mode already.

Go to the Dell support site, enter your Service tag number, it should tell you if it is setup in RAID.

 

[killbox]

I'm having problem getting the ahci to work. The register showed 0 all ready, but when I change to achi in bios and boot up it turns to bsod and boot loop.