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HD 6950 CF issue

Last response: in Graphics & Displays
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February 20, 2013 12:50:20 AM

I just (today, in fact) installed another 6950 to make my computer quite smashing. But, with crossfire turned on and all, I seem to get a choopiness to all the games that I play. All of my games, most anyway, run at 60 fps or higher according to fraps, so it is not an issue their. I did look at my CCC and found out that, while playing Crysis 2, the second card was only being used 1% and the first 75%. Anyone know what do?

More about : 6950 issue

February 20, 2013 12:52:37 AM

Also, not sure if related, but I cannot adjust my fan meter either. I mean, I can, but when I hit apply nothing happens. Should I roll back to the last stable version of Catalyst?
a b U Graphics card
February 20, 2013 1:10:33 AM

google microstuttering, and if you determine that that is your issue, then this fix in this toms article may be useful to you: (in general with CF you can have good FPS but crappy real world performance due to microstuttering...read up on it, this may fix your problem).

http://www.tomshardware.com/reviews/radeon-hd-7990-devi...

otherwise I'm not sure what to add about your current issue hopefully somebody can help you out there
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February 20, 2013 1:29:50 AM

I'm guessing it was microstuttering, because the help you linked seemed to reduce the choppiness by quite a lot, altough it still persists. Will look up on how to fix it more, thank you kindly.
a b U Graphics card
February 20, 2013 2:29:01 AM

No problem, glad to help out, try to continue fiddling with the settings on this dynamic v-sync stuff since it has worked so far it should keep working to reduce and get rid of the problem.

Make sure you are setting the FPS limit below your monitor's refresh rate and at a value close to or (judging by a quick read of how it works) I would say slightly below the Avg FPS. you are getting in a particular game.

Also turn the in game v-sync off, maybe that would help out? or turn it back on if turning it off causes your monitor to tear (if you don't know what monitor tearing looks like try youtube-ing or googling that, im sure youll find something).


And then other obvious things Im sure youve tried that I recommend .... make sure both cards are working, make sure you installed them in the correct slots on the Mobo, make sure you have the CF bridge.
a b U Graphics card
February 20, 2013 2:36:01 AM

Also... looking at your motherboard it seems it only supports Crossfire in a 16x and 4x configuration, having the second card in a 4x slot could be an issue if the 6950 saturates the bandwidth there ... do your research on this there is alot of information available as to how much a 16x4x CF setup will bottleneck certain graphics solutions.

And finally the last thing I can think of is make sure there is nothing in your PCI-E X1 slot in your mobo as this will reduce the bandwidth from the other two PCI-E slots where the GPUs are located


Also to answer your fan speed question, try to use MSI afterburner to set fan speed (google the program it's free and really really good and easy to use).
a b U Graphics card
February 20, 2013 2:49:07 AM

strohmz said:
I just (today, in fact) installed another 6950 to make my computer quite smashing. But, with crossfire turned on and all, I seem to get a choopiness to all the games that I play. All of my games, most anyway, run at 60 fps or higher according to fraps, so it is not an issue their. I did look at my CCC and found out that, while playing Crysis 2, the second card was only being used 1% and the first 75%. Anyone know what do?




Your mobo can only crossfire the second card at x4, on top of using an amd cpu with crossfire... Triple afflicted if you are not overclocking the cpu well.

I suggest you return the GPU, save some money and buy a single powerful card, preferably an nvidia card as they are less cpu dependant, then sell your original card.
a c 107 U Graphics card
February 20, 2013 2:59:25 AM

the only thing i can suggest is to use radeonpro and manually add profiles for heavy games you want to play

Best solution

a b U Graphics card
February 20, 2013 3:14:02 AM
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maxalge said:
Your mobo can only crossfire the second card at x4, on top of using an amd cpu with crossfire... Triple afflicted if you are not overclocking the cpu well.

I suggest you return the GPU, save some money and buy a single powerful card, preferably an nvidia card as they are less cpu dependant, then sell your original card.



I agree, a single GPU solution should have been what the OP pursued from the start given his motherboard, and AMD platform.

But that being said, the radeonPRO solution is a very powerful tool,

Tomshardware concluded in the article that "Aside from a few dropped frames and a handful of spikes when the test changes scenes, our dual-Tahiti card enjoys much smoother sailing. In fact, the end result is often better than what you'd see from a single graphics card, with virtually no micro-stuttering left."

My point here is not that Crossfire is better than single GPU, because I still agree with you, but that he can minimize all his stuttering so that the two 6950s basically act properly like a single card.... but this requires properly setting up the RadeonPro stuff for every game


In theory none of those issues, (having an AMD CPU, 16x4x mobo) should cause stuttering, even though they will ofcourse lower his Avg. FPS. IMO The OP needs to find an optimal FPS point to set the dynamic V-sync at, something that is a little below the average and definitely below the monitor's refresh rate.
February 20, 2013 3:16:06 AM

After tweaking for awhile, I finally got rid of all (except maybe a noticeable one every 10 minutes or so) micro stuttering on Crysis 2. But now, I only get about 20fps outside in the game for some reason. Ah well, looks like there's more work to do, although adding a profile for each game seams tedious and annoying, I've got nothing better to do.
February 20, 2013 3:24:47 AM

Best answer selected by strohmz.
a b U Graphics card
February 20, 2013 3:32:56 AM

Nice, that's good to hear radeonPro worked well...

I have one 6850 and I've been wanting to get a used one for cheap for a while...maybe ill do it now.

As for your low FPS, that probably has to do with your platform bottle-necking because a 6950CF should not dip that low unless the settings are too high (try lowering some settings... crysis 2 going from the ultra to the very high setting looked identical to me... but increased FPS alot... it's not a very memorable game though lol, you should play far cry 3... looked amazing and was the best game ive played in a long time).

Also at this point I think your CPU (and mobo but you cant do anything there) is the weakest point... so overclocking should produce nearly linear results, if you're comfortable with that.
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