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Windows 7: Ahci

27 Dec 2011   #1

W7x64 Pro, SuSe 12.1/** W7 x64 Pro, XP MCE
 
 
Ahci

Since I moved Windows 7 to a drive that has AHCI enabled in the BIOS, but the image that I used of Windows 7 was on a regular SATA drive previously, I didn't see the need to enable it in the OS. However, when I now transfer files from the AHCI drive (OS) to a regular SATA, I'm getting considerably lower transfer rate than before. Is this because of the current configuration?

Since the OS drive is the only one that is AHCI capable, would having AHCI enabled in the OS have any adverse effects on the other drives?

I read in the tutorial that AHCI had to be enabled in the BIOS before installing the OS, but since I didn't do a regular install, should I follow the tutorial's procedure for enabling it in the OS now, or would simply installing the AMD AHCI driver be sufficient?

My System SpecsSystem Spec
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28 Dec 2011   #2

Microsoft Windows 8.1 Pro 64-bit
 
 

Quote   Quote: Originally Posted by seekermeister View Post
Since the OS drive is the only one that is AHCI capable, would having AHCI enabled in the OS have any adverse effects on the other drives?

I read in the tutorial that AHCI had to be enabled in the BIOS before installing the OS, but since I didn't do a regular install, should I follow the tutorial's procedure for enabling it in the OS now, or would simply installing the AMD AHCI driver be sufficient?
Are you sure AHCI only effects the OS drive? I thought it effected them all. In fact, I've never heard otherwise and only ever hear of it being for all drives. Some raid configurations (Raid 0, etc) have multiple drives and distribute data to both drives. They need to be set on the RAID configuration (which uses AHCI) in the BIOS. http://en.wikipedia.org/wiki/RAID (the irony of using Wikipedia as a source. Oh well its accurate most of the time).

And no, it has no adverse effects on the other drives if it is enabled.

It does need to be enabled in the BIOS, and you do need the AMD AHCI driver (It probably will work without it, but why not have the correct driver installed? It can only help... usually). If it isn't working for you because of the OS transfer, try enabling it with the tutorial: AHCI : Enable in Windows 7 / Vista
My System SpecsSystem Spec
28 Dec 2011   #3

W7x64 Pro, SuSe 12.1/** W7 x64 Pro, XP MCE
 
 

Since I have never used AHCI before, I'm not sure about much, but I do know that a lot of hard drives are not AHCI capable. In fact, only one of my six drives on this computer is. As far as whether AHCI is working for me, the only indication is what I mentioned previously, the slow transfer speed of files from the AHCI drive to one which isn't. When it is working properly, does Windows indicate it in any fashion...like in the Device Manager or elsewhere?
My System SpecsSystem Spec
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28 Dec 2011   #4

Microsoft Windows 8.1 Pro 64-bit
 
 

Quote   Quote: Originally Posted by seekermeister View Post
Since I have never used AHCI before, I'm not sure about much, but I do know that a lot of hard drives are not AHCI capable. In fact, only one of my six drives on this computer is. As far as whether AHCI is working for me, the only indication is what I mentioned previously, the slow transfer speed of files from the AHCI drive to one which isn't. When it is working properly, does Windows indicate it in any fashion...like in the Device Manager or elsewhere?
Ah, sorry I didn't understand originally, thanks for clarifying seekermeister.

No, windows doesn't tell you if AHCI is working correctly, but the BIOS might. It does say if the driver is working correctly, but that doesn't help much here. Likely you would have to download 3rd party software to find exact transfer speeds and compare them to an ide setup to accuratly compare any drops or increases in speed. But I've not heard of any software that just lets you know if your AHCI setup is working correctly or not.

If your HDDs are older and not capable of running AHCI, then I would recommend just using IDE. Most of the time (unless you have an SDD) any speed differences are negligible, and it should fix your issue and (I would bet) put things back to normal speeds.
My System SpecsSystem Spec
28 Dec 2011   #5

W7x64 Pro, SuSe 12.1/** W7 x64 Pro, XP MCE
 
 

Thanks, but before reverting to IDE, I want to experiment some more with AHCI. Will simply installing the AMD driver enable this in Windows 7, or will I have to edit the registry also?
My System SpecsSystem Spec
28 Dec 2011   #6

Windows 7 Home Premium 64 bit
 
 

Try updating the chipset drivers.
My System SpecsSystem Spec
28 Dec 2011   #7

Microsoft Windows 8.1 Pro 64-bit
 
 

No, the driver will not enable it. It is for compatability, and stability, etc. It should even work without it, but I don't recommend that. Most people enable AHCI before installing their operating system in the BIOS (sounds like you said you have already), so it should be enabled right now.

However, You said you had transfered your operating system (An image, right?). So the registry may be incorrect right now, as the OS wouldn't have installed AHCI because the OS was IDE. AHCI is installed during the OS installation (if it detects you have it enabled in the BIOS).

So do use the tutorial if you would like to use AHCI. I think you have to do that and then reenable it in the BIOS, the tutorial will let you know.

As Sardonicus said, and I've added, make sure all drivers are updated.
My System SpecsSystem Spec
31 Dec 2011   #8

Windows 7
 
 

I managed to get AHCI working well on 2 really old XP installs without any registry editing, so I'm sure you can do it in Windows 7. I really can't remember all the details but basically do an image backup, then in Device Manager you install the AHCI stuff and ignore all of Windows many warnings about them being incompatible. Yes, they are incompatible, but nothing changes until you reboot and as long as you intercept the first reboot by going into the BIOS and select AHCI all will be well. Nearly all the advice on the net about having to install AHCI at operating system install time is wrong.
My System SpecsSystem Spec
31 Dec 2011   #9

Microsoft Windows 8.1 Pro 64-bit
 
 

Xp isn't windows 7 by any means. You'd need to actually test something like this before claiming it works
My System SpecsSystem Spec
31 Dec 2011   #10

W7x64 Pro, SuSe 12.1/** W7 x64 Pro, XP MCE
 
 

I just attempted to install the AMD AHCI driver, but it appears that the only things that it installed was the ATI Install Manager and the USB 3.0 filter driver. The install report list other devices, but records no action on any of them. The driver is an .exe, so one would think that it would handle everything itself, but apparently not. I thought about trying to install it from the Device Manager, but where would one install it...on a hard drive, the IDE ATA/ATAPI Controllers (If so, which one) or the storage controllers?

What more odd, is that going through the directrory where the installation setup is, I find all kinds of files for a lot besides AHCI, and nothing specifically labeled AHCI.
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