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Avoid AMD AHCI driver at all costs

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perdomot

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I had thought my AMD rig was moving slower than before even with my new SSD in place so I did some testing and found out that the AMD driver for my 785G mobos AHCI mode was killing performance, especially my WD HDD. I changed back to the MS AHCI driver and the numbers are much better. Curious if the Intel AHCI drivers can be used on an AMD rig and would they result in even better results. I posted the two before and two after ATTO benchies on Flicker for review:
http://www.flickr.com/photos/logan666pics/sets/72157624288866056/

Since this thread is prone to necromancy it's being locked. If anyone else wishes to discuss the issue, please start a new thread.
-ViRGE
 
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I thought AHCI was something I just selected in my BIOS and that was it.
Will I also have to download special drivers in Win7? Or will it be found and retrieved automatically with Windows Update?
 
Win 7 has its AHCI drivers that install automatically and they are better at performance but don't allow for hotswapping.
 
I remember somewhere that hotswap icon disappears when Win7 is installed on an SSD, though.
 
lopri said:
I remember somewhere that hotswap icon disappears when Win7 is installed on an SSD, though.
Click to expand...

Nope

msahci_hotswap.png
 
perdomot said:
I had thought my AMD rig was moving slower than before even with my new SSD in place so I did some testing and found out that the AMD driver for my 785G mobos AHCI mode was killing performance, especially my WD HDD. I changed back to the MS AHCI driver and the numbers are much better. Curious if the Intel AHCI drivers can be used on an AMD rig and would they result in even better results. I posted the two before and two after ATTO benchies on Flicker for review:
http://www.flickr.com/photos/logan666pics/sets/72157624288866056/
Click to expand...

Yes - there used to be a thread on the AMD/ATI forums though nothing ever came out of it.
The MS AHCI drivers CAN (don't have to) result in stuttering performance though (e.g. Win7MC Live TV will stutter)
 
MS driver shows eject but does not automatically detect a new drive. Intel driver does not show that eject (perhaps through RST for H57/Q57 though) but does automatically detect a new drive. Third-party HotSwap! utility works around both boners.
 
Auric said:
MS driver shows eject but does not automatically detect a new drive. Intel driver does not show that eject (perhaps through RST for H57/Q57 though) but does automatically detect a new drive. Third-party HotSwap! utility works around both boners.
Click to expand...

so that's why i have trouble trying to use my eSATA box
 
would be nice if the bad performance got some more attention (e.g. an Anandtech article).
This is a known issue for at least 1 1/2 years now with no fix in sight.
 
Yeah, I was reading this article when the write speeds of the HDD caught my eye:
http://www.techreport.com/articles.x/18539/8
My write speeds were about 30MB/s off from what they were supposed to be and when I changed my driver from the AMD one to MS, everything jumped back to normal. I wonder if the newer 8XX series ahci driver is any better and can even be used by 785G mobos.
 
Don't you guys just get slower speeds because with AMD driver you do not have TRIM capability? It's not like AHCI should influence sequential speeds anyway.
 
Well in my case, my mechanical hdd noticed a more than 30MB/s increase in write speeds just like in the above article where the H55 chipset beat the AMD solution on sata write speeds. With my ssd, the read speeds increased, most significantly starting with the 16.0 test and throughout the rest of the test. The system also feels more responsive but that is a subjective opinion. The most important thing I see is that if you are using a mechanical hdd as most people are and are going to make a Win 7/AMD rig, only use the MS drivers that come with Win 7.
 
coolVariable said:
The MS AHCI drivers CAN (don't have to) result in stuttering performance though (e.g. Win7MC Live TV will stutter)
Click to expand...
My brand-new Win7 install, using a full Intel chipset (P45) and ICH10R disk controller and a 320 GB WD SATA drive, was useless with the default MS AHCI driver. I'd click on an icon and it'd take 30 seconds before I could do anything else. As soon as I "updated" the driver to the Intel AHCI, it worked perfectly.
 
Intel's storage driver performance doesn't suck. AMD's does, as has been documented pretty well. Even its RAID performance, though better than its AHCI, lags behind Intel.
 
perdomot said:
On the contrary, AMD is excellent except their ahci driver. As long as you are using the Win 7 default ahci driver, you're fine.
Click to expand...

THAT is not true! The stuttering in Windows Media Center with the MS AHCI driver is evidence enough that there is some issue!!
I would have loved to know this 1 year ago when I upgraded my media center/server/desktop - I would have NOT bought an AMD.

DON'T BUY AMD UNTIL THEY FIX THIS!
 
You can use RAID mode with the RAID driver, just don't create a RAID volume (i.e. non-RAID disk). I prefer this to AHCI on AMD because it works, performance is better (though still not up to Intel), and you get all the enhanced features such as NCQ. Only caveat is, if you are using an SSD, you don't get TRIM support on Windows 7 in RAID mode.

I would like to see an Anandtech write-up article on AMD's piss-poor AHCI driver implementation? Maybe that would go a longer way towards getting AMD to take notice and do something. Its been an issue now for well over a year, going back to the first SB750 boards.
 
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coolVariable said:
DON'T BUY AMD UNTIL THEY FIX THIS!
Click to expand...

Or run AMD drives in legacy mode (called IDE stupidly enough by mobos... even though its not IDE, its just legacy ATA)

Keep in mind that AMD is a budget oriented company, for people who can't afford the quality of intel. Having things not work right is expected.
 
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