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AHCI Woes

Last response: in Windows 7
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February 17, 2011 4:07:44 AM

Attempting to change ACHI in bios in windows 7 ACHI does not show up in bios I am on a Gateway PC Windows 7 after changing settings in regedit to "O" rebooted clicked F1 until BIOS came up. Went to IDE selection cannot see any thing that says ACHI does not show up. Am I looking in the wrong place? Need specific instruction on window where located. Hope someone can help Thank you

More about : ahci woes

a c 244 $ Windows 7
February 18, 2011 1:48:02 AM

AHCI is a mode found under your SATA config. You usually have 3 choices for SATA modes (IDE, AHCI, and RAID).

Good luck!
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February 18, 2011 1:59:57 AM

Keep in mind that if you already installed windows on the drive that you are changing the SATA controller mode then you won't be able to boot into windows after you change the controller mode to AHCI. You either have to perform some driver and registry trickery prior to the mode switch or reinstall windows after the controller mode switch.
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February 18, 2011 5:56:38 PM

Hello Thanks for you response. This is what I was attempting to do. It main objective is to improve bootup performance. Not sure if this is a wise idea after reading your imput on rebooting after I have changed the registry. I don't want to have to reinstall Windows. I am assuming that this idea is a change that can be performed without having to reinstall anything. I may be wrong. Hope you can advise me. Thanks Xandr


Open up the Registry Editor by clicking Start | Run in Windows XP or by typing "regedit" into the Desktop search
box in Windows Vista and 7, and then type or click regedit to open up the registry editor. When the registry editor
is open navigate to this key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
Once there (Figure A), you will see the Start key, which is the key you need to edit.
Quick Tip: Improve your SATA disk performance by converting from IDE to AHCI
Page 2
Copyright ©2010 CBS Interactive. All rights reserved.
For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/
Figure A
Before you start modifying your registry, you might want to make a backup copy of that registry – just in case.
Right click the Start key and select Modify. When you do this another new window will open (Figure B). This new
window contains all of the data for the Start key. What you want to edit is the Value Data. Most likely your Value
will be set to “3”. You want to change that to “0” (no quotes).
Figure B
Make sure you change nothing but the Value Data.
Once you have made that change click OK. You can now close the Registry Editor.
Quick Tip: Improve your SATA disk performance by converting from IDE to AHCI
Page 3
Copyright ©2010 CBS Interactive. All rights reserved.
For more downloads and a free TechRepublic membership, pleas



The next step is to reboot your machine and then enter into the BIOS. Since every BIOS is different, all I will say
is that you need to enable the AHCI setting in your BIOS. When this is complete allow your machine to reboot and
hopefully you will enjoy a boost in performance. I say “hopefully” because not every machine will see a marked
improvement.
m
0
l
February 18, 2011 5:56:38 PM

Hello Thanks for you response. This is what I was attempting to do. It main objective is to improve bootup performance. Not sure if this is a wise idea after reading your imput on rebooting after I have changed the registry. I don't want to have to reinstall Windows. I am assuming that this idea is a change that can be performed without having to reinstall anything. I may be wrong. Hope you can advise me. Thanks Xandr


Open up the Registry Editor by clicking Start | Run in Windows XP or by typing "regedit" into the Desktop search
box in Windows Vista and 7, and then type or click regedit to open up the registry editor. When the registry editor
is open navigate to this key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
Once there (Figure A), you will see the Start key, which is the key you need to edit.
Quick Tip: Improve your SATA disk performance by converting from IDE to AHCI
Page 2
Copyright ©2010 CBS Interactive. All rights reserved.
For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/
Figure A
Before you start modifying your registry, you might want to make a backup copy of that registry – just in case.
Right click the Start key and select Modify. When you do this another new window will open (Figure B). This new
window contains all of the data for the Start key. What you want to edit is the Value Data. Most likely your Value
will be set to “3”. You want to change that to “0” (no quotes).
Figure B
Make sure you change nothing but the Value Data.
Once you have made that change click OK. You can now close the Registry Editor.
Quick Tip: Improve your SATA disk performance by converting from IDE to AHCI
Page 3
Copyright ©2010 CBS Interactive. All rights reserved.
For more downloads and a free TechRepublic membership, pleas



The next step is to reboot your machine and then enter into the BIOS. Since every BIOS is different, all I will say
is that you need to enable the AHCI setting in your BIOS. When this is complete allow your machine to reboot and
hopefully you will enjoy a boost in performance. I say “hopefully” because not every machine will see a marked
improvement.
m
0
l
February 18, 2011 6:14:34 PM

That all sounds good. Obviously if that registry edit doesn't work you'll have to get back into the BIOS and reset back to IDE, otherwise you're good to go.
m
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l
a c 244 $ Windows 7
February 18, 2011 6:50:17 PM

Also, the noticeable difference you will see between IDE and AHCI modes is not going to be monumental. If you aren't hot-swapping or running in RAID, the difference will largely be negligible. Regardless, good luck!
m
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l
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