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Windows 7: Sata Mode AHCI / IDE

02 Mar 2011   #1

Windows 7 Ultimate x64
Sata Mode AHCI / IDE

Hey everyone. I hope everyone is doing fine. I've literally rebuilt my entire machine but I think I made a mistake before installing Windows 7.

I should have gone over the BIOS with a fine tooth comb, but I did not. The SATA mode is set to IDE instead of AHCI or RAID and now of course, I can't switch it to my knowledge without getting a BSOD. It means I would have to reinstall the OS over again.

I have been reading up online and did a search here, but didn't find the appropriate thead. I have two questions. I read on a forum somewhere, where an Intel user used a program to change this in Windows somehow. Is there some kind of utility that will allow me to switch to AHCI mode without reinstalling Win7 64bit?

Second question, is it worth it to switch over? I see the benefits are this:

AHCI mode brings 3 main advantages:
Supports NCQ (Native Command Queuing) allowing SATA drives to accept more than one command at a time and dynamically reorder the commands for maximum efficiency.
Supports hot plugging of devices
Supports staggered spin ups of multiple hard drives at boot time

My machine seems kind of slow when accessing data and don't know if this is an issue with the SATA drives being in IDE mode. I got some choppiness in some games that's coming from access data (tested) and that seems weird but could definitely come from SATA drives being in IDE mode.

I got an MSI R5770 Hawk Video card...I'm freaking in love with that thing :)

I have two Hitachi 7200RPM SATA and one Seagate Barracuda 7200RPM SATA drive. All three are 500GB

My new machine is ASRock M3A770DE Mainboard and I successfully unlocked the 4th core on my AMD Athlon 445 making it a Phenom X4 3.1 and it's running beautifully. Ran a stability test and it was perfect.

RAM is Kingston HyperX CAS8 running at 1600mhz

So my AHCI or not. Do you think its worth it. Have you noticed huge performance gains.

So now I guess I better update my profile and sorry I haven't been around. Me and SevenForums had an email issue


My System SpecsSystem Spec
02 Mar 2011   #2

Windows 7 Ultimate x64

That's weird. I thought Windows 7 handled switching to AHCI mode better than that. Guess it has the same problem as XP.

Anyway, quick answers to a couple of your questions:

1) There is nothing magical about AHCI. About all you will gain is the ability to hot-plug drives. That may be worthwhile if you use an external HDD connected by eSATA. Otherwise, I wouldn't worry about it.

From what I've read, NCQ is only of real benefit in an environment where the disk is being accessed constantly, such as server. Normal desktop users probably won't see any measurable benefit.

The staggered spin-up thing probably doesn't matter either. Maybe it would, if you were running a large RAID (like maybe a 6-disk RAID 10) and had a barely-adequate power supply.

2) Yes, there should be a way to install the AHCI drivers so that Windows 7 doesn't bluescreen on startup. I did it with Windows XP, although it wasn't all that straightforward. I didn't have to reinstall Windows XP, and you shouldn't have to reinstall Windows 7 either.


Just for curiosity, I tried switching my disk controller to IDE mode. Windows 7 booted, but then made me reboot immediately, presumably because it had to install the IDE-mode drivers for the disk controller. On next startup, I re-ran the Windows Experience Index test. My disk score remained exactly the same (5.9) as when I had the disk controller in AHCI mode.

I then restarted, got into the BIOS menu & switched the disk controller back to AHCI mode. On restart, Windows 7 again booted fine.
My System SpecsSystem Spec
02 Mar 2011   #3

Windows 7 Ultimate x64

Hey thanks for the reply. I'll try to see if I can switch and see what happens. I don't think the Windows Index would change unless you replaced the drive with a solid state. 5.9 seems to be the best score you can get with a conventional hard disk.

Thanks for the reply.
My System SpecsSystem Spec

02 Mar 2011   #4

Windows 7 Ultimate x64

It might be informative if I ran a hard drive benchmark utility with the disks in both AHCI mode and IDE mode.

What would be a good testing utility? HD Tach has a trial version that will test for best-case (sequential) read speeds, which should be enough to show any differences between AHCI and IDE performance.

I didn't know mechanical HDD's could only score 5.9 on the Windows index. How about if you have them in a RAID 0 config? RAID 0, or one of its hybrids such as 1+0, can just about double read speeds in many cases.

I'll post results if I do get around to some testing.

Practically no difference, which is about what I expected.

Attached Thumbnails
Sata Mode AHCI / IDE-hdtune_ahci_on.png   Sata Mode AHCI / IDE-hdtune_ide_mode.png  
My System SpecsSystem Spec
02 Mar 2011   #5

Windows 7 Ultimate 64 - OEM Service Pack 1

Here you go my Man excellent tutorial for you from our very own Bare Foot Kid

AHCI : Enable in Windows 7 / Vista[2]=Performance%20Maintenance

My System SpecsSystem Spec
02 Mar 2011   #6

Windows 7 Ultimate x64 SP1

There are ways of swapping, but don't bother if you are going to expect a performance difference, because there won't be, not with a spinner.
My System SpecsSystem Spec
02 Mar 2011   #7

Windows 7 Ultimate x64

I just tried to switch...BSOD. So it's not possible anyway and for no performance gain, it's not even worth it to reinstall the OS.

Thanks for the replies everyone.
My System SpecsSystem Spec
02 Mar 2011   #8

Windows 10 Pro/ Windows 10 Pro Insider

It is possible, I have done it before. Just follow the tutorial Steve Pressman gave. But, I don't believe you will see much performance gain unless you have an SSD.
My System SpecsSystem Spec
03 Mar 2011   #9

Windows 7 Ultimate (x64)

This seems to depend on the BIOS and on the motherboard. I have posted my experience in the tutorial thread Steve mentioned, but let me repeat briefly. I have a Dell Inspiron 530, which I have upgraded to its max. When I bought a SSD, I decided to enable AHCI for it based on many accounts in these Forums and elsewhere. Trouble is, Dell Bios is very restricted, the only thing one can do is to switch from IDE to RAID. That (although not obviousl beforehand) does turn on AHCI. But, as much as I tried to enable AHCI in my old installation of Windows 7, I did not succeed. No matter what I do, if I boot the old Windows installation (installed for IDE) with the RAID/AHCI setting in the BIOS - the system will not boot, no BSOD, but right after initial animation the machine will reboot on its own. So for now I have to switch the BIOS setting every time I need to turn on another OS.

In addition, the eSATA experience also seems to be affected by this BIOS setting. Of course, my Dell mobo does not have a on-board eSATA, so I use a PCI-e card (made by Hama) with a JMicron chip. This is a RAID/AHCI card. Now, when I boot in IDE and then plug the external drive into the eSATA port on this card - everything works as advertised, although a bit slower than on my laptop which came with a native eSATA port. Now, if I boot into AHCI, then plugging the external drive into the eSATA card does not work. I am not sure if the two AHCI controllers are in conflict or something, I have not had the time yet to investigate this properly.

Now, since I am running two setups, one in IDE and one in AHCI, I can say that there is basically no difference between them, in every-day use. Of course, for the SSD AHCI is supposed to be better because of TRIM support, but that's "under the hood". On the surface, the SSD is definitely faster than HDD, although so far not as screaming fast as I believed it would after reading all the threads about them. But then, like I said, I only had very little time to play with the thing.
My System SpecsSystem Spec
03 Mar 2011   #10

Microsoft Community Contributor Award Recipient

Windows 7 Ult x64 - SP1/ Windows 8 Pro x64

I would recommend AHCI, you might not notice a performance improvement, but NCQ can reduce the HDD activity and disk thrashing.
If you're using eSATA it's nice to be able to remove the external when you want to.
The tutorial listed by steve-pressman does work very well.

@unifex, I switched from IDE to RAID on my Dell Inspiron 530, before the reg edit trick was known. Loaded the RAID drivers and when it asked to re-boot I went to the BIOS and switched it to RAID, after the OS loaded it asked for another re-boot and I was in AHCI mode.

If this doesn't work for you, use the above tutorial.

As long as you have the RAID drivers loaded in the OS it will run in AHCI mode.
When it re-boots by itself does it run fine afterwards?

I never used a PCI-e card, got a SATA cable that went to a backplate with a eSATA plug on it, nothing else just cable.
Works great for over three years now, can hot swap with a nice little program called "HotSwap", it looks and functions just like the MS Safely Remove Hardware option, except it will clear the cache and let you unplug the external.
This method will also let you run an OS from an external, it has no way of knowing it's not internal.

If your SSD is not noticeably faster, there might be something that is holding the performance back. Bad alignment, old drivers, there are several things that could be doing it.
My System SpecsSystem Spec

 Sata Mode AHCI / IDE

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