I've been running a 780G mobo for a while now and from what I've been reading, their sata controllers have a problem running AHCI and so I'm forced to run in IDE mode. I'm concerned I'm taking too big a hit in performance as I have a Velociraptor hdd for my OS Drive and IDE mode prevents NCQ and hotswapping. I've been thinking of switching to a different chipset like the Nvidia 750a SLI but would like some feedback from users on this issue. Thanks.
Mobos and AHCI
- Thread starter perdomot
- Start date
lopri
Elite Member
- Jul 27, 2002
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Did you try AHCI on your board? In order for AHCI to work the followings should cooperate.
- Mobo chipset (south bridge, not north bridge)
- HDD firmware (some HDDs have aggressive caching mechanism thus cause conflicts with hot plugging)
- OS and drivers (generally newer OS and drivers are better, and if possible use native OS drivers)
- Mobo chipset (south bridge, not north bridge)
- HDD firmware (some HDDs have aggressive caching mechanism thus cause conflicts with hot plugging)
- OS and drivers (generally newer OS and drivers are better, and if possible use native OS drivers)
780G mobos should be able to run in AHCI. SB700 fixed the issues AMD boards had, it was the SB600 that was the problem (690G boards).
There's no need to switch mobos, though you may need to reinstall windows to get the OS drive to function in AHCI mode.
There's no need to switch mobos, though you may need to reinstall windows to get the OS drive to function in AHCI mode.
I stopped using ACHI since I do not hot swap, and I am a single user so I don't need NCQ (more of a high demand utility as when multiple users are tapping drive). I also read (2007) that AHCI can slow performance in games and such. Not sure its true but I did see it in some reviews and articles. The F6 install was always a pain and I was glad to just use IDE and be rid of ACHI.
I originally installed XP in IDE mode so I'd have to reinstall windows. From reviews I've read, even the new SB750 still has problems with AHCI:
http://www.techreport.com/articles.x/15256
The average write speed is very disturbing.
http://www.techreport.com/articles.x/15256
The average write speed is very disturbing.
ACHI can be activated in windows without the need the reinstall.
In XP all you need to do is isntall the correct ACHI drivers and then activate ACHI (if you get the drivers wrong you can just disable it and try again).
In vista it is even simpler, since the drivers are already installed even if you installed the OS in IDE mode, all you need to do is change a registry key, its easy to google.
Personally I noticed a fairly dramatic speedup in loading time, when I activated ACHI in vista.
In XP all you need to do is isntall the correct ACHI drivers and then activate ACHI (if you get the drivers wrong you can just disable it and try again).
In vista it is even simpler, since the drivers are already installed even if you installed the OS in IDE mode, all you need to do is change a registry key, its easy to google.
Personally I noticed a fairly dramatic speedup in loading time, when I activated ACHI in vista.
From their review, they didn't even test AHCI. They just have a single line about "AMD's unresolved AHCI issues." AFAIK, 790G motherboards may not have the fastest SATA performance, but AHCI works well without any major problems.
Also, AHCI won't help much for games, but it helps when trying to have multiple concurrent file transfers of any type.
According to the article, the SB750 is the same as the SB700 except the for the ACC and the SB700 is a die shrink of the SB600 which had problems. I checked their site and found an article showing the differences between IDE and AHCI:
http://www.techreport.com/articles.x/13832/5
Apparently, running AHCI results in either high cpu usage or poor performance on AMD rigs while not on a competitors like Nvidia. I have two high performance hdds in my system, one for OS and one for storage, and the low write speeds really concern me. I also use esata for backups and I have to use a workaround to get the system to see the backup drive when I turn I on. I'd like it to just detect it like it does with firewire and usb.
Fox5, are you using IDE or AHCI mode on your rig and is it an AMD one?
http://www.techreport.com/articles.x/13832/5
Apparently, running AHCI results in either high cpu usage or poor performance on AMD rigs while not on a competitors like Nvidia. I have two high performance hdds in my system, one for OS and one for storage, and the low write speeds really concern me. I also use esata for backups and I have to use a workaround to get the system to see the backup drive when I turn I on. I'd like it to just detect it like it does with firewire and usb.
Fox5, are you using IDE or AHCI mode on your rig and is it an AMD one?
Here's a link from the same site showing the SB700:
http://techreport.com/articles.x/14261/10
Performance doesn't look improved from the AHCI compared to SB600, but at least the high cpu utilization is gone.
Still, is the performance lower than not using AHCI? It looks about the same compared to the review where they run in IDE mode, slightly lower perhaps but in the same ballpark.
So it looks like AHCI on the SB700/750 platforms doesn't bring about any performance benefits, but if you need the features of SATA, you get them at really no loss.
I've set up 3 computers for friends on the SB750 running in AHCI or RAID, and 1 computer for myself as well that was used as my HTPC. Never noticed any problems.
My main rig is Intel though, and uses a JMicron controller.
http://techreport.com/articles.x/14261/10
Performance doesn't look improved from the AHCI compared to SB600, but at least the high cpu utilization is gone.
Still, is the performance lower than not using AHCI? It looks about the same compared to the review where they run in IDE mode, slightly lower perhaps but in the same ballpark.
So it looks like AHCI on the SB700/750 platforms doesn't bring about any performance benefits, but if you need the features of SATA, you get them at really no loss.
I've set up 3 computers for friends on the SB750 running in AHCI or RAID, and 1 computer for myself as well that was used as my HTPC. Never noticed any problems.
My main rig is Intel though, and uses a JMicron controller.
lopri
Elite Member
- Jul 27, 2002
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I have been using AHCI and RAID on SB750 for some time to a satisfaction. (Vista & W7) It may not be as advanced as ICH but for a desktop usage it's more than fine, IMO.
And having said that, AHCI doesn't bring a meaningful performance gain on a desktop system. So that leaves hot swapping as a main advantage. If you need hot swapping by all means go for AHCI. But if not, remember that NCQ doesn't improve performance on a desktop and legacy IDE mode is much more broadly compatible. NCQ will be even more meaningless once SSD becomes prevalent.
And having said that, AHCI doesn't bring a meaningful performance gain on a desktop system. So that leaves hot swapping as a main advantage. If you need hot swapping by all means go for AHCI. But if not, remember that NCQ doesn't improve performance on a desktop and legacy IDE mode is much more broadly compatible. NCQ will be even more meaningless once SSD becomes prevalent.
Fox5 & lopri,
The tremendous difference in sata average writes is what really gets my attention in that review. The hotswap ability is important as well since I use my external hdd with esata. I actually replaced my OS hdd with my old raptor 74gb this morning and installed the new W7 RC in ahci mode and I have to say that the system feels much faster than my old XP in IDE mode did. Not sure if its W7 or running in ahci is the main factor though. The hotswap function works well with internal hdd connections but the esata on the back of my mobo didn't detect the external hdd when I turned it on. I used the bracket that came with the drive to connect to one of the mobo headers and when I turned it on, the pc detected it right away. Very odd.
The tremendous difference in sata average writes is what really gets my attention in that review. The hotswap ability is important as well since I use my external hdd with esata. I actually replaced my OS hdd with my old raptor 74gb this morning and installed the new W7 RC in ahci mode and I have to say that the system feels much faster than my old XP in IDE mode did. Not sure if its W7 or running in ahci is the main factor though. The hotswap function works well with internal hdd connections but the esata on the back of my mobo didn't detect the external hdd when I turned it on. I used the bracket that came with the drive to connect to one of the mobo headers and when I turned it on, the pc detected it right away. Very odd.
AHCI is perfectly fine in the SB700 and SB750, techreport just doesn't know how to properly turn it on.
1) enable ahci in bios
2) install raid drivers into windows / slip stream into OS and install OS
3) install ATI Raid tool
4) go to drive in ATI Raid tool and enable NCQ if it is disabled which is on most computers
profit
I don't see cpu usage go up but I do have longer boot times. But I use 2 eSATA drives and 1 big internal so I needs me some hotswap ahci.
1) enable ahci in bios
2) install raid drivers into windows / slip stream into OS and install OS
3) install ATI Raid tool
4) go to drive in ATI Raid tool and enable NCQ if it is disabled which is on most computers
profit
I don't see cpu usage go up but I do have longer boot times. But I use 2 eSATA drives and 1 big internal so I needs me some hotswap ahci.
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