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

 

[Bare Foot Kid]

Hello Gu1air, welcome to Seven Forums!



I'm glad you found a solution; thanks for the post.

 

[atlcraig]

Dave76

My SSD is my C drive. The is why I got the boost in Performance. I have downloaded the performance software you suggested, but haven't had time to run it yet. When I do I will post the results on the places you said.

 

[Dave76]

Looking forward to seeing them

 

[roknrob]

Add my kudos for an excellent and straightforward fix! Thanks!

 

[Bare Foot Kid]

Hello roknrob, welcome to Seven Forums; I'm glad it could be a help.

 

[siadi]

Question: Do these steps work for Windows XP Professional as well?

you can update your SATA controller driver to the AHCI version using the right driver(s) then reboot ur machine and set AHCI in BIOS to enable (whatever the words are in BIOS)

no AHCI drivers message appeared or asking to restart, is there anyway to verify is active?

if u can get to windows after setting it then it works.

Just an update of what I found out about ahci performance! After I installed and got ahci working I checked for any performance change in Windows 7 hard drives. My drive performance before I changed to ahci was 5.4 and after the change it was still 5.4. I then installed a SSD as my C drive and my drive performance went from 5.4 to 7.1! If I would have known this before I started I don't think I would have changed to ahci. So my advice to anyone wanting to increase the drive performance on their system would be to go out and buy a SSD.

basically SSD is much much faster than harddisk, so the WEI gain is very understandable.

imho and based on my own experience after setting AHCI in win7, benchmarks don't justify real-time performance but i see significant gain in copying large files (mkv files @ 1-8gb)

now the Q : after setting AHCI i got my 2 harddisks showed in the Safely Remove Hardware systray icon. is there any way to solve this? coz i think it's a bit annoying.

 

[ZaLiTH]

now the Q : after setting AHCI i got my 2 harddisks showed in the Safely Remove Hardware systray icon. is there any way to solve this? coz i think it's a bit annoying.

To quote from Wikipedia, and to be honest I thought it would have more on AHCI, but apparently not... Anyway, to explain why AHCI mode shows your drives in the 'Safely Remove Hardware' list:

AHCI is separate from the SATA 3Gb/s standard, although it exposes SATA's advanced capabilities (such as hot-plugging and native command queuing) such that host systems can utilize them.

 

[siadi]

now the Q : after setting AHCI i got my 2 harddisks showed in the Safely Remove Hardware systray icon. is there any way to solve this? coz i think it's a bit annoying.

To quote from Wikipedia, and to be honest I thought it would have more on AHCI, but apparently not... Anyway, to explain why AHCI mode shows your drives in the 'Safely Remove Hardware' list:

AHCI is separate from the SATA 3Gb/s standard, although it exposes SATA's advanced capabilities (such as hot-plugging and native command queuing) such that host systems can utilize them.

so the quote is saying that my drives being shown in "safely remove" list due to this hot-plugging capability.. cmiiw. thx man.. then i will have to pay extra attention when removing external devices after this hehehe

 

[ZaLiTH]

so the quote is saying that my drives being shown in "safely remove" list due to this hot-plugging capability.. cmiiw. thx man.. then i will have to pay extra attention when removing external devices after this hehehe

Yup, that is correct.. I've had to do much the same, but at least here we can be glad that MS finally got Windows to show the volume label in the 'Safely Remove Hardware' list! Something that should've been included since XP as far as I'm concerned... You do get quite used to it though.

@ Bare Foot Kid:
Just a thought, but I only just noticed your open post doesn't really mention any reasons or benefits for switching to AHCI.. Thinking about it now, I actually went to Google it and see what AHCI was and what was different to normal SATA when I first found this tutorial.

Perhaps to enhance it a little bit, at the start you could mention a brief description of the NCQ process (more info here) that AHCI uses? Might also be an idea to mention that AHCI also enables hot swapping support for SATA devices.. Just some constructive criticism, hope you don't mind.

 

[Bare Foot Kid]

Hello ZaLiTH, this is the first paragraph in the tutorial; reasons and/or benefits are subjective, at best, so I didn't want to go into that; this is just to show people a way to accomplish this, thanks though.​

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.​

 

[ZaLiTH]

Hello ZaLiTH, this is the first paragraph in the tutorial; reasons and/or benefits are subjective, at best, so I didn't want to go into that; this is just to show people a way to accomplish this, thanks though.​

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.​

Yeah, I guess that does pretty much cover it hey.. Lol.

 

[Bare Foot Kid]

Hello ZaLiTH, this is the first paragraph in the tutorial; reasons and/or benefits are subjective, at best, so I didn't want to go into that; this is just to show people a way to accomplish this, thanks though.​

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.​

Yeah, I guess that does pretty much cover it hey.. Lol.

No probs mate!

 

[matrixgaby]

I have Windows 7 installed in my PC on IDE mode. Now i want to put HDD in AHCI mode. I have 2 HDDs : 1 x Seagate 160 GB SATA NCQ & 1 x 120 GB Maxtor IDE.
I´ve done what it´s written on first page, but after enabling AHCI mode in BIOS, I have a problem. It´s saying something about initialising AHCI mode and list quickly my two HDDs (it happen very fast, so this is what I think is shown). After that it remain stuck at a black screen, where it is only 2 characters : ¨¨j_¨¨.
The motherboard is an AsRock M3A785GMH/128.
Am I doing something wrong?
Please help.

 

[Bare Foot Kid]

Hello matrixgaby, welcome to Seven Forums!



Is the OS booting from an SATA or a PATA/IDE HDD?

 

[matrixgaby]

The OS is booting from SATA HDD Seagate 160 GB NCQ drive.

 

[Bare Foot Kid]

Hello matrixgaby.



Did you create a restore point before you started this?

 

[matrixgaby]

Yes, I created. But if I switch back to IDE mode in BIOS, Windows is booting correctly.
My question is how to make AHCI mode to work and what ¨¨_j¨¨(what appear on the black screen) means?

 

[Bare Foot Kid]

Yes, I created. But if I switch back to IDE mode in BIOS, Windows is booting correctly.
My question is how to make AHCI mode to work and what ¨¨_j¨¨(what appear on the black screen) means?

I don't know what that may mean, maybe something went wrong the first go round and you can use the restore point to go back before the change and set it back to IDE and in a day or so give it another go, maybe by then someone will shed some light on the issue for you. Just be sure to create restore points before and after and do keep us informed.

 

[matrixgaby]

So, what I mean is that I don´t needed the restore point cause when i see that it was stuck at that black screen, I restarted. I entered BIOS, changed HDD mode back to IDE and after restart booted succesfully in Windows.
The problem is that dows not want to boot with AHCI enabled.

 

[Bare Foot Kid]

So, what I mean is that I don´t needed the restore point cause when i see that it was stuck at that black screen, I restarted. I entered BIOS, changed HDD mode back to IDE and after restart booted succesfully in Windows.
The problem is that dows not want to boot with AHCI enabled.

It is possible Windows 7 may not have the correct AHCI drivers for your motherboard and you may have to find and install the correct drivers on your own, that does happen some, have a look around Google to see what you find and post back to keep us informed.