Sign in to follow this  
Burner27

Is enabling AHCI worth it?

Recommended Posts

I have the option to enable AHCI just like anyone else and i have AHCI-capable HDDs. I am just wondering if it is worth it? I am not sure what software i would use to benchmark such a change. Does anyone have any personal experience they could share? I have a WD Velociraptor as my OS/Apps drive and 4 x 1TB HDDs.

Thx

Share this post


Link to post
Share on other sites

It is worth it only if you want/need the features that AHCI provides:

1. More than 4 SATA hard disks

2. Native Command Queuing (NCQ)

3. (possibly) Fake RAID

The general consensus seems to be that NCQ is generally a winner for servers and a loser for desktops. FRAID is regarded as just evil.

As far as I know, the only downside to having AHCI is if you've previously installed Windows in non-AHCI (my BIOS calls this Compatibility) mode. Windows doesn't take kindly to the switch.

I generally run in AHCI mode, but have seen no problems (other than 2 of my hard disks not being seen) in Compatibility mode.

Share this post


Link to post
Share on other sites
It is worth it only if you want/need the features that AHCI provides:

1. More than 4 SATA hard disks

2. Native Command Queuing (NCQ)

3. (possibly) Fake RAID

The general consensus seems to be that NCQ is generally a winner for servers and a loser for desktops. FRAID is regarded as just evil.

As far as I know, the only downside to having AHCI is if you've previously installed Windows in non-AHCI (my BIOS calls this Compatibility) mode. Windows doesn't take kindly to the switch.

I generally run in AHCI mode, but have seen no problems (other than 2 of my hard disks not being seen) in Compatibility mode.

Well I run Vista and Win7 in dualboot and they both support AHCI natively. I just had to edit the registry first then reboot and change the BIOS to enable AHCI.

I did experience one of my TB HDDs 'disappearing' like you said when using AHCI. Previously under 'IDE' mode, none of my drives disappeared. I am assuming this is a 'weirdity' of AHCI?

Share this post


Link to post
Share on other sites

The NCQ implementation from WD doesn't yield a big effect in my experience. However with a Seagate drive I felt that using NCQ results in a more responsive system. It is probably not really quicker but it feels like it was.

Share this post


Link to post
Share on other sites

AHCI also allows for hot swapping, reading of SMART data (which some controllers don't support in emulation mode), power management (i.e. turning off the drive while idle, which not all controolers support in emulation mode) and many other things.

To be honest, I don't see the benefit in not enabling AHCI. Basically you're buying a SATA drive and running it in non-SATA mode.

While there may be no major benefit of turning on AHCI if you do not use any of these features, there's no benefit - even theoretically - of leaving it off and running in emulation mode.

Share this post


Link to post
Share on other sites
The NCQ implementation from WD doesn't yield a big effect in my experience. However with a Seagate drive I felt that using NCQ results in a more responsive system. It is probably not really quicker but it feels like it was.

Weaker, can you please explain this?

I have not come across any other hard drive except 7200.11 750GB that does not stutter my system and they are not even boot drives (no hd activity).

I have an Intel SSD and it doesnt even cut it.

Intel X25-M (Boot - NCQ)... Copy a 10GB file to it... And try playing a movie. It stutters and skips and can't even open very lowprint Miranda IM. Lag.

Seagate 1TB 7200.11 (Non-Boot - NCQ): Copy a 10GB file to it... And try playing a movie. Stutters and skips.

Seagate 750GB 7200.11 (Non-Boot - NCQ): Copy a 10GB file to it... Run a virus scan... Encode a 1GB video... Zip a 10GB file... And try playing a movie... It works smooth, everything is responsive.

Intel X25-M (Non-Boot - NCQ): Same crap.

Seagate 750GB 7200.11 (Boot - NCQ): Everything works fantastic even with 5-6 simultaneous disk-operations even though this drive is boot drive.

So for me, Intel X25-M did not make a difference at all. I would take Seagate 750GB any time of the day. Now I have SSD boot drive and I needed more space so replaced 750GB with 1TB... What a torture! I could not take the it more than a day and back to 750GB. Tried 1TB WDs, Samsungs and still no go.

You'd think I have asked a really hard question?

That question has been answered. There is a whole 20 pages thread about that i posted. Do your homework.

Share this post


Link to post
Share on other sites
The NCQ implementation from WD doesn't yield a big effect in my experience. However with a Seagate drive I felt that using NCQ results in a more responsive system. It is probably not really quicker but it feels like it was.

Any measurable data? Few months ago, I was interested in this topic and I was watching this thread.. AFAIK the result of that discussion was, that WDs implementation of NCQ is functional too.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this