Disabling AHCI BSOD

BizSAR

New Member
Hello!

I have what seems to be a rare issue since I can't find any help on the subject.

I installed Vista Ultimate 64-bit with AHCI successfully. Now, I would like to disable AHCI and revert back to eIDE. When I make that change in the BIOS, I get the 0x0000007B BSOD until I reset the BIOS back to AHCI support. Just the opposite of the issues I'm seeing other people reporting. :p
When I run a Vista repair, it reports everything as functional.

All of the information I can find discusses enabling AHCI, not the other way around.
I'm running an ASUS P5KE-WiFi AP mobo utilizing the latest BIOS.

Any thoughts?
 

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System One

  • CPU
    Intel Q6600
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    ASUS P5KE-WiFi AP
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    eVGA 8800GTS 512MB
Hi Bizsar,

When you install Vista using AHCI mode you can not change it without reinstalling Vista again.

Steven
 

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Thank you very much for the reply.

Respectfully, I simply cannot believe that I have to reinstall, when there is a MS KB article that explains a workaround for the exact opposite problem when the exact BSOD occurs. If I don't have to reinstall to enable AHCI, why would I need to reinstall if I wish to disable AHCI?

As you may know, and as explained in the KB article, the issue that causes the 0x7B BSOD is that the AHCI driver in Vista is disabled, and the KB article goes on to describe enabling the driver in the registry. It seems to me the inverse is happening here: The eIDE driver has been disabled, and it seems simply finding the correct registry key and enabling it would do the trick. The issue at hand, therefore, is finding the correct registry key/subkey. Is this oversimplification of the issue?

I find it very odd that this has not come up before, especially since so many people (like myself) mistakenly believe that AHCI is going to improve HD performance on a basic system that isn't being used in a server capacity, especially on a gaming system, and wish to disable AHCI to improve HD performance for sequential access applications (like games).

UPDATE: It looks like the two drivers that need to be enabled just might be pciide and intelide...
 
Last edited:

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System One

  • CPU
    Intel Q6600
    Motherboard
    ASUS P5KE-WiFi AP
    Memory
    4GB Crucial Ballistic Tracer DDR2
    Graphics Card(s)
    eVGA 8800GTS 512MB
Hey Bizsar,

There might be a way to enable the drivers after installing in AHCI mode Im just not sure..., the only problem I can see stoping you is Vista didnt load anything with IDE support since AHCI superceeds the IDE specifications and even conflicts with it hence the difference in mode settings...

Keep us updated, I will let you know if I find anything...
Steven
 

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Well, while there is a definite possibility that certain IDE support files need to be installed still, the MSKB article you linked has you change the key value to "0" to enable AHCI. When the value is 0 to enable, the opposite value is "1" to disable so you could try that for starters.

This bit from the MSKB article makes me believe that the IDE drivers were NOT installed during your Vista installation since you chose the AHCI option...just as Steven pointed out above

MSKB Article said:
During the Windows Vista installation process, any unused storage drivers are disabled. This behavior speeds up the operating system's startup process. When you change the boot drive to a driver that has been disabled, you must enable the new driver before you change the hardware configuration.

If you can find all the proper files and register anything needed with Windows services to enable IDE, it's possible that you may not have to reinstall Vista, however..I think if you do a Repair Install and enable IDE during that, you can get this al back and save your data and installation.
 

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System One

  • Manufacturer/Model
    Personal Build
    CPU
    Intel E6750 Core 2 Duo
    Motherboard
    Asus Commando MoBo (P965/ICH8R)
    Memory
    4G's Crucial Ballistix Tracer DDR2 PC26400 RAM
    Graphics Card(s)
    BFG 8800GTS OC2 320MB
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Well, I messed around with it some more, and failed. So I did just reinstall.

I'll work at it some more and post my findings later.

Thanks for all your help. :)
 

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System One

  • CPU
    Intel Q6600
    Motherboard
    ASUS P5KE-WiFi AP
    Memory
    4GB Crucial Ballistic Tracer DDR2
    Graphics Card(s)
    eVGA 8800GTS 512MB
I'm curious about this as well. I installed Vista64 w/AHCI enabled and my HD performance has been great. Unfortunately the disappearing DVD drive of doom pissed me off so much I've enabled the jmicron IDE controller and hooked up an old DVD-ROM drive instead of the sata drive I was using before.

Long story short, I can either re-install w/AHCI disabled or buy a better IDE DVD-RW drive and just use that. :D
 

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Well, I messed around with it some more, and failed. So I did just reinstall.

I'll work at it some more and post my findings later.

Thanks for all your help. :)

Dear BizSAR:
since you both using ACHI and IDE , could you psot the performance differemce between ACHI and IDE ( same harddisk) ? I just wonder the result, I also heard from many people they said ACHI open will improve the performance , but I not sure
 

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Well, I messed around with it some more, and failed. So I did just reinstall.

I'll work at it some more and post my findings later.

Thanks for all your help. :)

Dear BizSAR:
since you both using ACHI and IDE , could you psot the performance differemce between ACHI and IDE ( same harddisk) ? I just wonder the result, I also heard from many people they said ACHI open will improve the performance , but I not sure

AHCI is bad for games and playing music because its not good with synchronised read/writes, Its only good for file servers... IDE gets way better performance.
 

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Hi Bizsar,

When you install Vista using AHCI mode you can not change it without reinstalling Vista again.

Steven

That's not true. All that needs to be done, is the registry edit of setting in the registry as in the below instructions to 1, instead of zero, reboot, then disable AHCI mode in the bios. I've done this many times and it works.

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.

Note number 6, as in the instructions above, which came from Microsoft, that the Value in the registry entry showen in Number 4, must be set to 1. Then reboot, go in to the bios disable AHCI mode, then boot back in to Windows Vista, and Windows Vista will install the IDE driver, and redetect any harddrives in the system.

However if the person has used the Intel Matrix Storage driver for the AHCI driver, that the user most likely will not be able to uninstall the Intel Matrix Storage driver.
 

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That's not true. All that needs to be done, is the registry edit of setting in the registry as in the below instructions to 1, instead of zero, reboot, then disable AHCI mode in the bios. I've done this many times and it works.

Last time I checked for a method there wasn't information about a successful way of disabling AHCI mode after installing Vista.

Does this work if you had enabled AHCI then installed Vista before switching back it IDE mode or only after installing using IDE then switching to AHCI and wanting to swtch back later?

Steven
 

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Yes, this works for me if I install in AHCI and then switch to IDE mode, or going from IDE mode to AHCI, and then back to AHCI.
 

My Computer

System One

  • CPU
    Core 2 Duo E6600
    Motherboard
    Intel 975XBX2
    Memory
    8GB's of DDR2 800
    Graphics Card(s)
    Radeon 3870X2
    Sound Card
    HT Omega Claro
    Monitor(s) Displays
    Viewsonic VG2030wm Widescreen LCD
    Screen Resolution
    1680X1050
    Hard Drives
    120GB
    200GB
    320GB
    PSU
    ThermalTake Toughpower 700
    Case
    Antec P182
    Cooling
    four 120mm fans
    Keyboard
    Microsoft Natural Multimedia Keyboard
    Mouse
    Microsoft Wireless Intellimous Explorer 2.0
    Internet Speed
    10MB
    Other Info
    16X LG DVDROM & LG Dual Layer DVD Burner
    Logitech X-540 speakers
Yes, this works for me if I install in AHCI and then switch to IDE mode, or going from IDE mode to AHCI, and then back to AHCI.

Cheers WildEagle, Thats some useful information, Did you want to make a Tutorial for anyone who would need a procedure for re-enabling IDE?
 

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I'll make one. Might be a little while, got my head stuck in Mass Effect on the PC.
 

My Computer

System One

  • CPU
    Core 2 Duo E6600
    Motherboard
    Intel 975XBX2
    Memory
    8GB's of DDR2 800
    Graphics Card(s)
    Radeon 3870X2
    Sound Card
    HT Omega Claro
    Monitor(s) Displays
    Viewsonic VG2030wm Widescreen LCD
    Screen Resolution
    1680X1050
    Hard Drives
    120GB
    200GB
    320GB
    PSU
    ThermalTake Toughpower 700
    Case
    Antec P182
    Cooling
    four 120mm fans
    Keyboard
    Microsoft Natural Multimedia Keyboard
    Mouse
    Microsoft Wireless Intellimous Explorer 2.0
    Internet Speed
    10MB
    Other Info
    16X LG DVDROM & LG Dual Layer DVD Burner
    Logitech X-540 speakers
Yes, this works for me if I install in AHCI and then switch to IDE mode, or going from IDE mode to AHCI, and then back to AHCI.

Cheers WildEagle, Thats some useful information, Did you want to make a Tutorial for anyone who would need a procedure for re-enabling IDE?

That is fantastic, even though it's a lot simpler than I would have thought (simply reversing MS' own directions for switching to AHCI). I can safely tell you that those are the only instructions for switching back from AHCI on the 'net. I searched through countless numbers of Google searches.

wufawutian: unfortunately I didn't benchmark my HD with AHCI enabled, so I don't really have data to compare to my current setup. That's something else I can't find: gaming benchmark comparisons between AHCI and e-IDE.
 

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System One

  • CPU
    Intel Q6600
    Motherboard
    ASUS P5KE-WiFi AP
    Memory
    4GB Crucial Ballistic Tracer DDR2
    Graphics Card(s)
    eVGA 8800GTS 512MB
Have you tried it anyway?
 

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System One

  • CPU
    Intel Q6600
    Motherboard
    ASUS P5KE-WiFi AP
    Memory
    4GB Crucial Ballistic Tracer DDR2
    Graphics Card(s)
    eVGA 8800GTS 512MB
I haven't had a chance to hook up the sata dvd-rw again. Been super busy w/work lately. Will try it soon though and see if the Intel driver fixed the disappearing drive problem. Then I'll really worry about uninstalling the thing.. :)
 

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Yes, this works for me if I install in AHCI and then switch to IDE mode, or going from IDE mode to AHCI, and then back to AHCI.

Cheers WildEagle, Thats some useful information, Did you want to make a Tutorial for anyone who would need a procedure for re-enabling IDE?


Hmmm...I thought I mentioned that a little earlier in the post...guess nobody saw it eh
;)

Chappy said:
the MSKB article you linked has you change the key value to "0" to enable AHCI. When the value is 0 to enable, the opposite value is "1" to disable so you could try that for starters.
 

My Computer

System One

  • Manufacturer/Model
    Personal Build
    CPU
    Intel E6750 Core 2 Duo
    Motherboard
    Asus Commando MoBo (P965/ICH8R)
    Memory
    4G's Crucial Ballistix Tracer DDR2 PC26400 RAM
    Graphics Card(s)
    BFG 8800GTS OC2 320MB
    Sound Card
    Creative Sound Blaster X-FI Platinum FATAL1TY (next)
    Monitor(s) Displays
    2 x 22" w2207 LCD Monitors
    Screen Resolution
    1- 1680 x 1050, 1 - 1920 x 1080
    Hard Drives
    3 x 500G SATA II WD Caviar HDD's
    PSU
    EnerMax NoiseTaker II 600W
    Case
    NZXT Lexa Classic (modified, dual doored & windowed)
    Cooling
    Zalman 9700 CPU cooler, 4-120mm fans, 1-90mm
    Mouse
    Logitech Optical Trackman trackball
    Other Info
    NZXT Lexa Classic Case, Zalman 9700 CPU Cooler, 2 DVD Burners c/w LightScribe (Sony, TSST), Enermax NoiseTaker II 600W PSU with Custom Chrome cable sleeving, Hauppauge HDTV TV Tuner Card, 5.1 Logitech Z5500 speakers, 15 in 1 Multi-card reader
I have recently enabled AHCI with exactly the same reference, My machine, 64 bit Ultimate T-61 was running in compatability mode. I went to the registry to enable it there, and my value was a 4(for some reason unknown), which I changed to a 0 to enable it like the article suggests. Just thought I would add this!

Cheers,

Singtoh
 

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