AHCI : Enable in Windows 7 / Vista

Due to problems that I'm still dealing with in W7, I have not yet gotten XP reinstalled, but when I do, there is a driver for a floppy that I think is for the Marvel controller on my MB. I imagine that it include AHCI, but I won't know until I get to that point. If it is, then XP will be running ACHI, but W7 won't, because the drive that it is installed on is not capable of it. This leaves me wondering if I still need to enable AHCI in W7, so that any access/writes done from there would be utilizing AHCI properly?

Dear Bare Foot Kid,

Background Story:
My friend recently got an 2TB external with an Esata connection but his computer kept messing up with it. So we decided to do a reformat and enable the ACHI before format like it is recommended (he was already planning a reformat, this was just an added bonus).

After setting AHCI on We got to the Windows install screen and deleted the 2 partitions (reserve and normal) and ran the format. However windows gave us an error saying:
"Windows cannot be installed to this disk. This computer's hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's BIOS menu."

We tried several things to get around it including unplugging all other hard drives from the computer and using your guide to get a clean reformat (SSD / HDD : Optimize for Windows Reinstallation). Nothing worked so we gave up and put the computer back into IDE and installed Windows 7 fine.

However, we still wanted to get AHCI working so we used this guide to try to turn it on. First, we did all the Windows updates that were popping up and downloaded and installed the latest bios and chipset for his motherboard (A780GM-A V1.1). Then we followed this guide and restarted. It got past the motherboard information but then gave a black screen stating that no OS could be found.

We then restarted and went to the bios and looked to see what it was booting from. It appeared that the hard drive was not showing up. So we went to the boot menu and found the hard drive and booted from there which found the OS and started windows fine, automatically downloading the AHCI drivers.

To make it find the hard drive to boot from, we went back to the bios and looked under the advance CMOS settings but still couldn't see what hard drive was showing up in the 1st/2nd/ect boot order. So we went to the hard drives option and set his to the first one and looked again under the boot order. It showed up so we selected it and started up windows fine.

Result:
We plug the Esata in and it instantly detects the external drive. This was not occurring before the reformat. We moved a file from the external to his desktop and it shows ~120MB/s speed and finishes in a several seconds.

Problem:
Then we tried to move a file from the desktop to the external. It reports a 400MB/s speed and the bar fills up to ~75% (it is a 600MB file) but stops. This was one of the problems that was occurring before the reformat. The file stops transferring and the computer starts to lag a bunch till it freezes completely. Hitting "cancel" causes the file transfer to sit forever attempting to cancel, with no results. Opening task manager sometimes shows multiple explorer.exe's running. All can be ended except one and the file transfer won't stop, sitting there frozen. Attempting to restart the computer results in the computer sitting on the "logging off" screen indefinitely, requiring a hard reboot. Only after restarting, which takes 1-2 mins longer than normal, can we do anything on windows again.

Do you have any idea what my be causing the file to be unable to transfer to the external? We also tried mine which is the exact same as yours and the same problem. Mine also worked fine on my computer with Esata. Now we are about to try finding AHCI drivers specific for his motherboard and see if that fixes the problem.

I tried this once before a while back only to find out my bios did not support AHCI. I have since replaced that motherboard and know the new bios does support AHCI.

Before I try this I wanted to ask if my 3 SATA drives must also be compatible. And, if so, how I can find out easily?

SJMaye said:

I tried this once before a while back only to find out my bios did not support AHCI. I have since replaced that motherboard and know the new bios does support AHCI.

Before I try this I wanted to ask if my 3 SATA drives must also be compatible. And, if so, how I can find out easily?

Being SATA drives, they will be compatible. As per the AHCI Wiki page:

The Advanced Host Controller Interface (AHCI) is a technical standard defined by the Intel Corporation that specifies the operation of Serial ATA (SATA) host bus adapters in a non-implementation-specific manner.

Essentially that it means the 'compatibility' side of AHCI comes from how the 'SATA Controller' accessed the SATA drives. The drives will still spin up and read / write as instructed, but they will simply be instructed differently by the controller.

Thank you ZaLiTH.

I read the same things, but wanted to be sure. I will give it a shot.

golem said:

Ok, I knew I'd have a hiccup attempting this. During install of my OS a few weeks ago I tried to enable AHCI but kept failing boot so I just stuck with IDE and all has been working well. Figured why not give it a try now that everything is running smoothly. I added a restore point, modded the reg then enabled AHCI in the bios. Upon reboot BIOS starts listing the HD's then as the rest of that particular page is rendering I notice the primary drive listing disappears. Towards the end of BIOS initialization I'm greeted with a notification that no OS is available to boot.

After double checking that I hadn't inadvertently change something I shoulden't have in the BIOS I decided to do a "System Restore" via "System Recovery" off the retail disk. Unfortunately when I get to the System Recovery's option of choosing which OS the apply the restore point to I have no OS to choose from. For some reason it's not detected.

Any suggestions?

Hey mate that happened to me too, a few weeks ago, I found out the problem was the option UNDER the option to enable AHCI was causing the operating system to not be recognized, I didnt realize that until I did a new install! Not really game to try it again!.