Windows 7: AHCI : Enable in Windows 7 / Vista

Which HDD is your boot drive? SATA or IDE?

When you changed the BIOS setting from IDE to AHCI did you save & exit?

Don't know much about AMD AHCI drivers besides reading that some people are having trouble with them.
Some are using the Intel AHCI drivers and reporting success.

Did you try booting to safe mode?

If this doesn't work, start your computer, go to BIOS set it back to IDE mode and see if it will boot.
If it does boot, it means your AHCI drivers were not loaded on the previous attempt to switch to AHCI mode.

Hello again atlcraig.


Dave has listed some very good things to check on, here is the tutorial on safe mode, be sure to post back to keep us informed.

Dave76,

I have 4 SATA drives, one of which is my C drive. I did save the changes in the BIOS.

It looks like the AHCI drivers were not loaded.

I was able to boot into safe mode, but only when I used my Windows 7 64 bit DVD. When I tried to reboot without using the Windows 7 disc I still get the message Error Loading OS.

When I changed the BIOS back to IDE and tried to reboot without the system disc I whould get the same message.

I think you are right that the AHCI drivers were not loaded. I am not sure where to go from here next. I may have to call Microsoft and see if they will/can help me. I think that since they had nothing in the documentation that came with the system I really think it is a Microsoft problem and that they should help anyone having this type problem. We'll see if they think the same way.

Thanks for the help. I still can't get the computer to boot without having the Windows 7 setup disc in the computer.

atlcraig

Dave76

One other thing - I am not running raid and do not want to. For AHCI to work do you have to be running raid? It was my understanding that you didn't have to. Do you know if this is correct? Thanks again for the help - atlcraig

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

The answer is NO, you do not have to be in/using RAID for AHCI to work.
AHCI is a separate function from RAID, actually selecting RAID will put the computer in AHCI mode.

Your choices in BIOS are IDE, AHCI or RAID mode.
When you set your computer to RAID (normally the third option in your BIOS) it will set it to AHCI mode.
You can set your computer to RAID (which uses AHCI mode) and not have any HDDs set up in RAID configuration. You will have the advantages of AHCI when in the RAID setting.

The main benefits of AHCI are your HDDs can be HotSwappable (plug and play and unplug, without shutting down the computer), NQR (native command queuing, this allows your HDD to run more efficiently), allows the use of S.M.A.R.T. the HDD monitoring software.

Some people say it will provide a slight, noticeable, speed improvement, I did see an improvement by enabling mine. Also required for SSDs to use Trim function.

AHCI is:
Read the wikipedia site linked below and it will explain what AHCI is.

Click here >> Many SATA controllers offer selectable modes of operation

Hello WS.


No they do not, XP will not boot when AHCI is enabled in the BIOS, it'll blue screen; when I was booting XP and Windows 7 I had to change back and forth between AHCI and IDE mode depending on the OS I wanted to boot to.

Dave76,

I have found what my problem is and that is that after I enabled AHCI for some reason it changed the sequence of my drives. I am able to go into the BIOS and select the drive that I want to boot from and everything works just fine.

I had to try each of the drives until I found the right one! I have 4 SATA drives and 2 IDE drives and 14 partitions. I am now trying to find out why the boot drive that the system was using before AHCI was installed was changed because I don't want to go into the BIOS and make the change each time I boot the system. If anyone has an answer to this question I'm all ears!

Thanks again to every one for all the help. This is agreat web site and I am sure glad I found it.

Hello again atlcraig.



Change the boot priority in the BIOS to boot from the HDD you need it to boot from, have a look at the tutorial at the link below; be sure to post back to keep us informed.

Boot Priority - Change - Vista Forums

Bare Foot Kid,

thanks for the help.

I found mine under the BOOT heading and then under HARD DISK DRIVES. The instructions said to use the arrow keys to select the drive you wanted to move and then use the + to move it up and – to move it down. When I tried that nothing happened. I then tried the Pg Up and Pg Dn keys and they worked! I now have all of the drives in the right order and the system is now booting up just fine. I’m glad you found where to do the change and that made me look until I foun the place to make the changes on my computer.

atlcraig