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AHCI/NCQ or IDE emulation?

Posted: Thu Apr 03, 2008 3:26 pm
by zeroneleven
Relevent specs:
Gigabyte GA-EP35-DS3P (w/ ICH9R SATA controller)
Intel E8400
WD3200AAKS (2-platter model) SATA II HDD (system drive)
WD6400AAKS SATA II HDD

I'm just about to install WinXP on a new "silent" build, but I have one question first. In the BIOS, should I set the SATA controller to AHCI mode or keep it at the default IDE?

I understand I would need the SATA drivers during installation of XP. If I go that route, I can easily slipstream them onto the CD using nLite since I didn't install a floppy drive.

The real question here is whether Native Command Queuing (NCQ) is a) even supported by my system hard drive (WD3200AAKS), and b) if it is, am I likely to see any "real world" performance benefit? I'm using this computer as a single-user digital audio workstation only - no gaming, internet, etc. - so there will be several CPU intensive apps running at once.

Thanks.

Re: AHCI/NCQ or IDE emulation?

Posted: Thu Apr 03, 2008 5:02 pm
by AVT
zeroneleven wrote:Relevent specs:
Gigabyte GA-EP35-DS3P (w/ ICH9R SATA controller)
Intel E8400
WD3200AAKS (2-platter model) SATA II HDD (system drive)
WD6400AAKS SATA II HDD

I'm just about to install WinXP on a new "silent" build, but I have one question first. In the BIOS, should I set the SATA controller to AHCI mode or keep it at the default IDE?

I understand I would need the SATA drivers during installation of XP. If I go that route, I can easily slipstream them onto the CD using nLite since I didn't install a floppy drive.

The real question here is whether Native Command Queuing (NCQ) is a) even supported by my system hard drive (WD3200AAKS), and b) if it is, am I likely to see any "real world" performance benefit? I'm using this computer as a single-user digital audio workstation only - no gaming, internet, etc. - so there will be several CPU intensive apps running at once.

Thanks.
With Windows XP, you will need to make a floppy with the controller drivers before you can set the drive as ACHI and have it recognized by Windows XP.

If you set it as IDE, and install like that, Windows XP will not let you install drivers, and you will get a bluescreen if you boot with it as ACHI.

edit: Vista will see the drive automatically if you set ACHI.

Re: AHCI/NCQ or IDE emulation?

Posted: Thu Apr 03, 2008 10:45 pm
by zeroneleven
AVT wrote:With Windows XP, you will need to make a floppy with the controller drivers before you can set the drive as ACHI and have it recognized by Windows XP
You can install the drivers with a floppy (using the F6 key during installation) OR you can slipstream the drivers directly onto the WinXP CD. I use the program nLite (http://www.nliteos.com) since it lets you set up a customized, streamlined installation CD in addition to integrating drivers, service packs, hotfixes, etc.
AVT wrote:If you set it as IDE, and install like that, Windows XP will not let you install drivers, and you will get a bluescreen if you boot with it as ACHI.
That's correct, although there is a way around that problem without having to reinstall the OS - read about it here.

The question I'm still wondering is whether AHCI, and particulary NCQ, will make any significant difference in terms of performance. I've seen lots of conflicting information regarding the supposed benefits of NCQ.

Posted: Thu Apr 03, 2008 11:10 pm
by nick705
From everything I've read on the interweb, there's zero performance benefit to enabling NCQ in a single-user environment, and it can actually hurt performance under some circumstances.

Furthermore, there seem to be quite a few reports of certain drives behaving oddly with AHCI enabled on the ICH9R chipset - for instance, according to a thread on the Abit forums, the 1TB Samsung F1 can be temperamental in combination with the IP-35 Pro mobo, depending on what SATA port it's attached to and how many ports are occupied in total. I'm not certain if it still holds true in IDE mode, but in any case there's no point introducing further complications if there's no good reason to do so.

I'd stick with tried-and-tested IDE mode if I were you, unless you need hot-swappability for one or more of your drives. :)

Posted: Fri Apr 04, 2008 7:51 am
by HammerSandwich
EDIT - Disregard! I just looked at the workaround, and XP + AHCI is obviously complicated.
==========================

Trying it both ways should be less effort than you might think. Note that I've not tried this particular trick, but have done similar ones successfully. Make a system-drive image before you begin!

Doing a normal install in IDE mode is no problem, so start there & test. To switch:
* install the AHCI drivers
* use devmgmt.msc to uninstall the HDs & IDE
* reboot
* change the BIOS setting
* wait for XP to reinstall in AHCI mode

Posted: Sat Apr 05, 2008 6:57 am
by Jokoto
Here's a different set of instructions that I used last time. I'm not going back to the F6 method since this worked so well. On the other hand, if NCQ/AHCI is not beneficial (I never bothered to test this), next time I may just leave it out altogether.

HOWTO: enable AHCI mode after installing Windows

Posted: Sat Apr 05, 2008 12:25 pm
by Lawrence Lee
IMO, NCQ does not make a difference. However, I always use AHCI for my main system so I can hotswap SATA drives.

I did it recently on an EP35-DS3R, but went about it a different way. I installed Windows via the Gigabyte SATA2 controller, then installed the Intel Matrix storage driver, switched the native Intel SATA controller to AHCI mode in the BIOS, and finally moved my hard drive to an Intel port. Worked like a charm.

Posted: Sat Apr 05, 2008 12:53 pm
by mbetea
Is it XP with any service pack? I do believe at least with SP2 you do not need any SATA drivers (Hit F6) if you're using the HDD(s) in a non-RAID setup. At least I never had to with a 36gb Raptor and various motherboards.