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HD 6850 CF Low Performance

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a b U Graphics card
June 3, 2011 10:21:38 AM

Hi Everyone,
In April I purchased two AMD HD 6850s and I've got them running in crossfire mode, after reading plenty of reviews I thought these cards had great scaling, but it seems that on almost every game I run I get negative scaling or a tiny performance increase.

Here are some examples:
F1 2010 in Crossfire - 30 to 45FPS
F1 2010 W/O Crossfire - 35 to 55FPS

DiRT 3 in Crossfire - 62FPS
DiRT 3 W/O Crossfire - 68FPS

Crysis 2 in Crossfire - 45-60FPS
Crysis 2 W/O Crossfire - 50-60FPS

As you can see, there is no increase with crossfire in any of these games, the same can be said for pretty much any other game I play, however benchmarks seem to scale very well.

I'm running the latest version of CCC 11.5b with the 11.5 CAP 4. I don't understand why it runs so terribly, I hope somebody can help me.

Thanks a lot,
Tristan

More about : 6850 low performance

a b U Graphics card
June 3, 2011 1:22:54 PM

try 11.2/3/4 they should work, did you check temperatures?
a b U Graphics card
June 3, 2011 2:07:37 PM

lower minimum fps huh, sounds like my 6870s that I have since abandoned...
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a b U Graphics card
June 3, 2011 2:08:13 PM

I am pretty sure that crysis 2 does not utilize crossfire very well if at all, also what are your full system specs?
a b U Graphics card
June 3, 2011 4:34:02 PM

Thanks for your replies, I'll try version 11.2 3 and 4 when I get home later and I'll also check the temperatures when I get home, I used to have Crysis 2 working much better than it does now, it used to average at around 80 - 110 fps, but then it just changed.

Thanks for the help so far.
a b U Graphics card
June 3, 2011 5:39:33 PM

yeah a clean driver install should set you straight but from my experiences crossfire drivers suck
a c 125 U Graphics card
June 3, 2011 7:45:33 PM

Did you install the crossfire bridge?

Have you tried a driver uninstall and driver sweep before reinstallation?

Have you double and triple checked the the cards are both full inserted in the motherboard?

What motherboard do you own?

Have you checked what GPUZ says?

Are there any errors in the Crossfire tab of CCC?
a c 106 U Graphics card
June 3, 2011 8:27:20 PM

Crossfire has some significant CPU overhead, always has though they seem to be better about it now. If your CPU is the limiting factor in games then crossfire actually can lower the FPS since in addition to your CPU not being fast enough to provide one card with information, it needs to take cycles to divide up the work between the cards. You can hardly blame the cards for that.

What's the rest of your system? Did you re-install the drivers and make sure that the crossfire bridge is properly inserted?
a c 106 U Graphics card
June 3, 2011 8:45:55 PM

I also want to add that your single card performance seems a tad low as well unless you're using eyefinity, so I'm sticking with my hunch that your CPU is the problem.
a b U Graphics card
June 3, 2011 9:11:26 PM

wolfram23 said:
Did you install the crossfire bridge?

Have you tried a driver uninstall and driver sweep before reinstallation?

Have you double and triple checked the the cards are both full inserted in the motherboard?

What motherboard do you own?

Have you checked what GPUZ says?

Are there any errors in the Crossfire tab of CCC?


1) Haven't Yet, what program should I use to ensure a full driver sweep?
2) Both cards are most definitely, positively, affirmatively in place
3) I have an ASRock M3A770DE, Not great I know, but isnt that bad
4) GPU Z says that crossfire is enabled with 2 GPUS
5) There are no errors in the Crossfire tab on Catalyst
a b U Graphics card
June 3, 2011 9:16:27 PM

Here is the rest of my system specs,
CPU - AMD Athlon II X4 635 @ 3.1GHZ
RAM - 4GB DDR3
MOBO - ASRock M3A770DE
HDD - 500GB WD Caviar Green
Res - 1920x1080

I am about to try the previously mentioned drivers and I will report back

a c 125 U Graphics card
June 3, 2011 9:40:54 PM

Also when you installed the CAP, did you uninstall old versions?

As for driver sweeping, I always use Driver Sweeper. http://www.guru3d.com/category/driversweeper/

Seems that CF is indeed enabled and should be working. One other thing, can you run MSI Afterburner and play one of those games? Just play for maybe 10 mins then go back and look at the graphs - make sure you have GPU usage and the core/mem clocks enabled at the least (and it's a good idea to make the graphs very big so they record and display more data). I'm wondering if the 2nd card isn't getting usage.

Oh right and which 6850s do you have, which model?

Older drivers shouldn't be better than 11.5 but sometimes you can be unlucky.

One other thing to try is to use each card on it's own in the primary slot and make sure that they each work individually.
a b U Graphics card
June 3, 2011 10:45:52 PM

Okay, I've got a fresh install of my Display drivers and CCC, this time, version 11.3, seems to run slightly smoother in crossfire. I took note of the GPUs usage, GPU 1 runs at around 40 - 50% and GPU 2 runs at 60-78%. So it's the first card not being utilised as much, a bit weird.
a c 125 U Graphics card
June 3, 2011 10:51:59 PM

Ah, interesting. They should be nearly identical to eachother. Are they different models of 6850? And have you tried swapping out which one is on top?

Also, just to clarify something, the best method for reinstalling drivers is:
-uninstall CAP (add/remove programs)
-uninstall drivers (add/remove programs)
-run driver sweeper and remove all ATI display drivers
-reboot. resolution should be ultra low (800x600)
-install new drivers
-install CAP
a b U Graphics card
June 3, 2011 11:05:12 PM

They are the exact same model, there the Gigabyte OC versions. Havent swapped them around yet, will do it tomorrow as its midnight now. Thats pretty much how I installed the drivers, except I couldnt use driversweeper because I couldnt download it from Guru3D and the download I found elsewhere contains the program but doesnt work.
a b U Graphics card
June 3, 2011 11:08:10 PM

I have since switched my CPU clcoks between 2.9GHZ, 3.1 and 3.4GHZ with no noticeable change in performance
a c 217 U Graphics card
June 3, 2011 11:52:08 PM

Can you post GPU-Z screenshots for both cards? I have a feeling that your 2nd card is running at x4 or so.
a b U Graphics card
June 4, 2011 9:57:08 AM

Yes, my motherboard supports crossfire in x16 + x4, I knew it would have a slight affect on performance but surely not this bad?
a b U Graphics card
June 4, 2011 10:02:56 AM

Just tested Crysis 2 for the first time after getting the older drivers and it runs at about 110FPS on the same mission where I was getting about 50FPS previously, and also I no longer get terrible lag when V-Sync is off and no black shadow in the middle of the screen on max settings.
a b U Graphics card
June 4, 2011 10:17:41 AM

just as i thought.
a b U Graphics card
June 4, 2011 11:44:09 AM

All the other games are still suffering though
a c 217 U Graphics card
June 4, 2011 3:52:44 PM

Did you also download the crossfire profiles when you got the drivers?
a b U Graphics card
June 4, 2011 7:23:34 PM

Yes, I'm using the latest CAP
!