Switching SATA from IDE Compatibility mode to AHCI in Windows

[MacClipper]

by MacClipper (2007)

*** Please do NOT PM me with requests or questions, share them here so others can help out or benefit too, I do NOT answer such PMs so don't be offended if I don't. Kindly quote any reference to this guide with the whole url and do not reproduce any parts without my expressed permission. This guide is provided as is without any promises or compensation, thank you.

Aim - to accomplish the above without needing a complete re-installation or a repair installation of the OS.
For more advanced Windows PC users only.

MS KB922976 for Windows 7 or Windows Vista
eg. in W7 x64, original reg key values were both 3 instead of the 0 to be entered.

If you had previously installed Windows in IDE mode and now want to try out AHCI mode, you will need to jump through a few hoops cos merely switching to the AHCI mode in the BIOS will get you a nice shiny cryptic BSOD. This is also true for Windows Vista (yes, I tried) although Vista has built-in AHCI drivers which allow for a fresh Windows with AHCI install without the need for F6 floppy loading.

I prefer to install Windows with IDE mode and then switch over to AHCI once I have ensured that Windows is running as expected. imo, it is easier to troubleshoot under IDE mode cos in that mode, the Device Manager reflects the UDMA mode used wheareas there is no such indication under the AHCI mode. Encounters with ODD issues, bad SATA cables, failing PSUs (HD drops to PIO mode) have taught me this is the better way. Besides, I hate dealing with floppy disks especially since I haven't bought any for the longest time.

There are probably many ways to do so but I am going to elaborate on 2 methods which I have personally tried successfully on my Commando i965 & P5W DH Dlx i975 mobos.

Requirements
Intel SATA AHCI drivers in DOS format, the drivers are usually found on the mobo bundled disc but sometimes only as installers which have to be extracted in single file format (DOS format in Asus parlance).

I will attach the Commando bundled i965 AHCI drivers (both 32 bit x86 and 64 bit x64 versions) for reference so you will know roughly which files to look out for, of course you can try to use them too if you are running a i965 mobo. You can load these drivers on the HD itself or a thumbdrive or even from the bundled disc if it is available in DOS format - no floppies required. Just remember to find and use the appropriate ones for your particular mobo.

Let's make it simple (and prob. lengthy being step by step) and hencefoth I will refer to the harddisk containing your Windows OS as the HD. You may want to print out this guide so you can refer to it offline as well.

Method 1 (mobo with >1 SATA controllers)
If your mobo has an additional SATA controller eg. Jmicron (like my P5W DH Dlx), you are in luck cos this method mostly requires you to do a simple temporary cable swap.

1. Power down the PC

2. Swap the HD SATA cable from the Intel SATA controller to the Jmicron

3. Power on PC and enter the BIOS
a. Ensure the Jmicron is using IDE mode, next set the now Jmicron attached HD as the default boot disk.
b. Switch the Intel controller from IDE to SATA AHCI mode
c. Save BIOS settings and allow the PC to boot into Windows

4. Windows now auto-detects a new SATA AHCI controller has been found

5. Direct the Windows driver update wizard to the driver location and install, next Windows should ask to reboot.

6. Reboot and allow PC to go into Windows, check that the Intel SATA controllers are now in AHCI mode.

7. Power down and swap the HD SATA cable back from the Jmicron to the Intel controller.

8. Power up, enter BIOS and set the now Intel controller hosted HD as the default boot drive.

9. Save BIOS settings and reboot into Windows with AHCI now activated, enjoy.

...continued.

[MacClipper]

Method 2 (mobo with only 1 SATA controller)
If your mobo lacks any additional SATA controller like my Commando i965, it becomes a little more complcated in playing with the BIOS settings but it is still not that difficult as a complete re-install or a repair. There won't be any physical cable switching but more BIIOS IDE/AHCI option swtiching around instead.

1. Boot into Windows and ensure that your HD is indeed in IDE mode by checking the Device Manager.

2. Go to the controller hosting the HD and double click (or right click) to get to the driver details sub-page.

3. Click on Update Driver.

4. Select Update Manually. Do NOT use automatic update/search cos you will need to do a forced update.

5. Select Browse and point to the folder containing the DOS drivers.

6. Windows may complain that these drivers may not be suitable (since you are forcing AHCI drivers in IDE mode), ignore the warning and execute the update nonetheless. Don't fret cos you are switching modes on the next reboot.

7. Windows will next prompt you to reboot.

8. On POST, go into the BIOS and switch the controller to AHCI mode.

9. Save BIOS settings and reboot into Windows.

10. Windows now auto-detects a new PCI controller (yes, the SATA AHCI controller is PCI based) and installs the AHCI drivers and another reboot is required to use this new controller and drivers.

11. Reboot into Windows with AHCI now activated, enjoy.

Hope this guide has helped someone by easing the pain in getting AHCI and its supposed benefits, cheers.

Kindly post feedback in this thread if it has benefitted you (or otherwise) in doing the IDE-AHCI switch and do take part in the poll too. Just holler if you need more hand holding or maybe some screenshots, the number of pics are kind of limited in forum posts whch puts me off trying to do so.

Easy switching to AHCI in Windows Vista
Using a simple registry hack so this is much easier to follow. Just remember the original value is 4, I have tested this myself and it does work.
XtremeSystems Forums - View Single Post - p6t poor optical drive performance (ICH10R) (was dvd ripping)

Just Modify the following registry entry: 
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servic es\Msahci\Start

Set the Value = 0 
Reboot .. change BIOS to AHCI .. Save & Reboot ..

Else just download this reg file and double-click to implement AHCI on your Vista rig, just remember to do the BIOS switch as well when you reboot.
AHCI_Switch.reg

To go back from AHCI to IDE,
AHCI2IDE_Switch.reg

Using the Hotswap! utility screenshots in W7 x64,
HotSwap!

Right click,


Left click,


Left click remove,



Error message when you start a Windows 7 or Windows Vista-based computer after you change the SATA mode of the boot drive: "STOP 0x0000007B INACCESSABLE_BOOT_DEVICE"

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To resolve this issue yourself, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:
Exit all Windows-based programs.
Click Start, type regedit in the Start Search box, and then press ENTER.
If you receive the User Account Control dialog box, click Continue.
Locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
In the right pane, right-click Start in the Name column, and then click Modify.
In the Value data box, type 0, and then click OK.
On the File menu, click Exit to close Registry Editor.

[MacClipper]

Sample drivers used,

Asus Commando bundled i965 AHCI drivers (both 32 bit x86 and 64 bit x64 versions) for reference as promised. These are actually from Intel itself and should work if you have a similar mobo esp. i965 based ones.

32 bit (tested on XP32),
http://www.sendspace.com/file/nyyt8z

64 bit (tested on XP64 and Vista x64 Ultimate),
http://www.sendspace.com/file/li8giq

Enjoy.

[TheTrap]

bro I'm on the NF Chipset leh...any Nvidia chipset guide ? this guide not applicable to me

[MacClipper]

erm, the principles and steps should be exactly the same if you are using Windows XP or Vista - just swap any mention of Intel drivers with Nvidia drivers lor. Of course, you will have to source for the discrete Nvidia AHCI drivers 1st.

[limcc]

for those using ICH9 or ICH9R on P35 board, download the intel Matrix storage driver 7.6.0.1011, may not work with other non-RAID ICHx southbridge/hub. read the readme text file for more details.

extract the storage driver using command switches. for example, the below command will extract the intel storage drive to c:\intel
iata76_enu -a -pc:\intel

you will have 3 folders with what Asus call "DOS" driver format.

[TheTrap]

thing is , I can't tell the UDMA mode with NF chipset device manager doesn't show it

[Budweiser]

Thks MacClipper for the information.
I followed your method and it shows that it can work.

Here are two diagrams






I got one qn, the hd tune doesn't show what kind of interface it is running.
Is this normal?

Edit: the primary ide only connects to my benq 1640, the ahci is for wd 320gb aaaks.

[TheTrap]

so what performance increases are there ?

[MacClipper]

I got one qn, the hd tune doesn't show what kind of interface it is running.
Is this normal?

HDTune may need an update cos I get the same blank info display on my brand new 7200.10 500GB but full info display on my 1 year old 7200.10 250GB on the same PC ie. same PC/SATA config but 2 different HDs give different reports.

To Tim, go read up on AHCI vs IDE mode leh eg. hot plug, NCQ & multi-tasking... real life performance probably vary for different user usage patterns. You can always switch back to IDE if you find AHCI not up to your expectations.

[TheTrap]

even so , I still can't find out what mode my HDDs are running at.....

[Budweiser]

Lets wait for an update for hd tune.

[MacClipper]

even so , I still can't find out what mode my HDDs are running at.....

It's easiest to see the PIO/UDMA communication mode if you are using the default MS XP drivers rather than 3rd party ones like nVidia, Jmicron or Intel. With the default MS drivers, the controller will be identified as "Standard Dual Channel PCI IDE Controller". btw, your question has nothing to do with attempting the IDE -> AHCI switch but more about nVidia IDE driver comm. mode reporting capability.

A gentle reminder again as mentioned in the 1st post,

For more advanced Windows PC users only.

Don't blame me for anything if anyone screws up their Windows installation trying the AHCI switch hor, you better know your Windows well enough before attempting stuff like this. It's actually very easy and safe but one can never tell...

[TheTrap]

yep it be much easier if I were on a more common chipset T_T

[asphodeli]

It's easiest to see the PIO/UDMA communicationmode if you are using the default MS XP drivers rather than 3rd party ones like nVidia, Jmicron or Intel. With the default MS drivers, the controller will be identified as "Standard Dual Channel PCI IDE Controller". btw, your question has nothing to do with attempting the IDE -> AHCI switch but more about nVidia IDE driver comm. mode reporting capability.

A gentle reminder again as mentioned in the 1st post,


Don't blame me for anything if anyone screws up their Windows installation trying the AHCI switch hor, you better know your Windows well enough before attempting stuff like this. It's actually very easy and safe but one can never tell...

Hi MC, might want to add on your article to create 2 hardware profiles in WinXP in case something goes terribly wrong