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Weird GPU oscillation (GTX 560Ti)

Discussion in 'bit-tech Folding Team' started by vasileioszografos, 26 Apr 2012.

  1. vasileioszografos

    vasileioszografos New Member

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    So I have two GTX 560Ti cards in SLI mode and do some folding with them.
    In general they are ok but sometimes especially when I leave the PC running overnight, I notice that there is a strange oscillation on the use of the two cards.

    Thus normally they are both at 100% usage by the Folding client, during the oscillation one goes to 100% then the other to 0% and then they reverse. This keeps happening ad infinitum. You can see this as spike oscillations in the GPU usage graphs. They are symmetric of course.
    The CPU client still folds but the whole system (Windows GUI etc) just slows down to a halt.

    Any ideas what can cause this?
    It is not overheating I am sure.
     
  2. Leroyingo

    Leroyingo New Member

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    Check the nividia control panel. The power management mode- change it to maximum performance (under 3d settings). When set to adaptive it can stop the GPU from running at full load all the time.
     
  3. vasileioszografos

    vasileioszografos New Member

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    Nope. Still does the same thing. Happens only after a few hours of data crunching
     
  4. vasileioszografos

    vasileioszografos New Member

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    ok so I have done some research into the problem and it seems to be SLI related. Although SLI works just fine in games in the folding it seems to cause these oscillations. Quite interesting because it didnt use to do before.

    Now something more interesting. I've added a GeForce 9600 GS into the same rig with my two GTX560Tis.

    I have disabled SLI and used Matlab to test concurrent CUDA evaluations on all 3 GPUs. I could max them at a sustained 98-99%. No probs.

    Enter FAH. Chose 3 cores. All say running. No error messages. Only one of the 3 cards is actually doing any work at around 70%. Crap.

    For some reason the existence of the 9600GS messes up the client.

    If I remove the 9600GS then it will probably work for the two cards.
    Not sure what exactly is going on. It seems that the FAH_cores just remain dormant. When I quit the application the two FAH_core1.1 and FAH_core1.5 remain in memory.
     
  5. vasileioszografos

    vasileioszografos New Member

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    So now the 9600GS is removed and SLI disabled and FAH seems to work fine. I'll need to do a full's day run before I can be sure that this problem was indeed caused by the SLI and is now fixed.
     
  6. Christopher N. Lew

    Christopher N. Lew Folding in memory of my father

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    Mixing cards of different generations always used to cause trouble with the v. 6 GPU clients. Problems didn't seem to be reproducible on different machines, so it was assumed to be something wrong at a very low level.

    Can't help you with the GTX560 Ti problem, other than suggesting to turn SLI off. I think the bridge can stay in place.
     
  7. vasileioszografos

    vasileioszografos New Member

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    Strange that. Of well...the 9600 is now removed. too bad really because it could do a little bit of extra folding work. Now it will just have to collect dust

    Yeah I did. And folding now works fine. It is not that difficult to enable-disable it from the NVIDIA control panel.
     

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