why AHCI

[dbarton]

By default my new mobo says the SATA ports run in IDE mode.

My understanding is that I should change the bios to AHCI mode before installing XP, (and adding the drivers)

I did this once before, but WHY do I want AHCI and is it worth the trouble?

Also, I have 6 ICH10 Sata ports and 2 silicon image sata ports. I want the drives on the ICH10's. Is that right? I'm confused about why I have two different types.. Looks like the silicon image are for some kind of drive mirror function. (asus)

 

[The Keeper]

1) AHCI seems to have its own little issues, mainly poor implementation in consumer grade products, including Windows.

What AHCI is supposed to give you is NCQ and NCQ means Native Command Queuing. Which again means that in an environment where you have multiple concurrent reads and writes, NCQ is supposed to queue those in a way it takes the least spinning to get it done. At best, the performance improvement is noticeable. At worst, it is going to decrease your performance because of poor implementation in consumer grade products.

If you're using Windows, you're probably going to to have better luck with Vista than XP. Then you're going to have to pick right motherboard, Intel chipsets probably have the least problems with AHCI. Finally you gotta find yourself a HDD that performs well under Windows with NCQ enabled. One of those few drives that do is Seagate 7200.11.

On the flipside, most people aren't going to notice a difference in performance with NCQ enabled as opposed to without it. If you want to know more, feel free to go read storagereview.com forums.


2) ICH10 is preferrable. SI chipset probably also includes 1-2 IDE-ports for IDE-drives as ICH10 doesn't have any.

 

[dbarton]

Much appreciated. The system is a new Asus mobo with an Intel e85000, with XP. The boot drive is a Seagate 7200.11, so perhaps I have a combination that might work.
Then again, if it's just a small difference, maybe not worth bothering on just a basic home system.

The second drive is an older drive, but i'm not sure if that matters. Enabling AHCI only affects boot drives, or all drives?

I see the SATA ports on this mobo are set to IDE mode by default, so maybe that's a hint..

 

[RebateMonger]

Originally posted by: dbarton
I see the SATA ports on this mobo are set to IDE mode by default, so maybe that's a hint..

I have yet to install AHCI SATA drivers on any of my PCs. It's SOOO nice to not have to worry about drive controller drivers. Especially for a "basic home system" and for XP.

 

[The Keeper]

Some chipsets/BIOSes allow you to change operating mode per-port, but most only per-controller. So if you enable it on ICH10, it will affect all devices plugged to the ICH. If the drive doesn't support NCQ, it isn't enabled. However, in some cases it is known to cause quirky behavior, even with optical SATA-drives that don't support NCQ. Such devices are then best used on secondary SATA-controller (like the silicon image in your case) that uses IDE-mode instead.

At least when you use IDE-mode you know your drive won't be performing slower than it should under any circumstances (unless there is another problem), but on the other hand NCQ may situationally feel much more responsive. But can you be sure it is not just a placebo effect as you're hard pressed to test the drive's performance without synthetic benchmarks, which again may give more credit to NCQ than real world usage would.

Guess you just have to try both, at least you already have the 7200.11 which should be excellent candidate for trying it out.

 

[Blain]

Don't forget "Hot Swap"!

 

[dbarton]

The older drive is a Seagate 6H500F0 Diamond Max 11 with NCQ, so maybe it's not actually that old as to cause any issues.

Now there's also drivers for Marvell and no info on what they are in the manual. Are those AHCI drivers for the secondary SATA ports? If so, it seems better to leave secondary as IDE for the problems you guys mention above. Or have it go that wrong?

 

[The Keeper]

Even if the older drive supports NCQ, it may still perform slower than it should for mostly same reasons as many new drives do.

Marvell is quite likely your ethernet chipset.

 

[Synomenon]

I have a 300GB & 160GB Raptor, a 250GB Seagate 7200.10 and a LG SATA DVD burner all connected to my motherboard's ICH10R SATA ports and have AHCI enabled. No problems at all. The Seagate is in one of those external hard drive docks and AHCI lets me have the hot swap feature with that dock.

 

[mrSHEiK124]

Originally posted by: IsLNdbOi
I have a 300GB & 160GB Raptor, a 250GB Seagate 7200.10 and a LG SATA DVD burner all connected to my motherboard's ICH10R SATA ports and have AHCI enabled. No problems at all. The Seagate is in one of those external hard drive docks and AHCI lets me have the hot swap feature with that dock.

Hay! Me too!

I've got a 300 GB Raptor, 640 GB WD, and Pioneer SATA DVD burner connected to my ICH10R SATA ports and use AHCI to allow me to hotswap an e.SATA enclosure I have to use a few times a week.

 

[Slugbait]

I've got an 80G Raptor on a Bad Axe II. After my initial XP install without AHCI, I was kicking myself for spending a premium on that drive: the OS didn't finish loading any faster than my old machine (they were SxS), splash screens for Office apps sat on my desktop for several seconds, etc.

So I flattened the box, and re-installed with AHCI. Extremely noticeable performance increase.

AHCI is a YMMV...works great for some, no real difference for others.

 

[Pluto]

I went through a lot of effort to enable AHCI on my wife's computer the last time I reloaded Windows XP (after SP3 was released) and she swore it was slow and unresponsive, and the hard drive was thrashing a lot. It is an Asus P5K-VM (Intel G33) mobo, with ICH9 - I needed to do some crazy stuff with the ICH9 SATA drivers to get XP to recognize it (she was not ready for Vista....) I ended up switching back to IDE mode and she hasn't complained since. The drives were both Seagate, one an older 7200.7 and a 7200.10

I recently bought a couple new Gigabyte GA-EG45M-DS2H boards (Intel G45 chipset). One I set up with Vista x86 and a Seagate 7200.11 using AHCI - runs great
The other I used another 7200.7 I had lying around. Again, under AHCI the system seems very sluggish and the drive thrashes a lot (I thought this was Vista at first, but I disabled the indexing service and its still doing it)

I think the conclusion for me is AHCI is a bad idea unless using all brand new hardware, especially the drives.