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A few questions about multi-gpu setups.

Discussion in 'Graphics Cards' started by Upgrayedd, Aug 25, 2014.

  1. Upgrayedd

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    Can you have a 770 as your main card and lets say a 760 dedicated to PhysX or MSAA?
     
  2. RCoon

    RCoon Gaming Moderator Staff Member

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    For dedicated PhysX only, but a 760 would be a massive waste. You can use something with just a few hundred CUDA cores for dedicated PhysX, and it's a fairly small performance requirement. I managed a GTX 275 for dedicated PhysX in the past, and it barely went over 30% usage.
     
  3. Upgrayedd

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    Ok. so a dedicated PhysX card doesn't have to be much, got it. What about MSAA could I have dual 760s and run one for AA only?
     
  4. RCoon

    RCoon Gaming Moderator Staff Member

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    Not that I'm aware of. The only option for dedicated cards is PhysX processing.

    [​IMG]
     
  5. Upgrayedd

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    So if I want to run games with MSAA would I be better off getting the highest VRAM, fastest single GPU or a SLI setup?
     
  6. RCoon

    RCoon Gaming Moderator Staff Member

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    Whichever setup has more General GPU power in your case. I don't think much over 3GB VRAM is necessary for MSAA on 1080p despite it upscaling the resolution of everything.
     
  7. Upgrayedd

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    It would be on 1440p or 4K whenever I decide to build this winter. So for example say you had two 1,700cuda core GPUs in SLI, 4GB each, lets say scaling is right and all that. Would they handle MSAA better at higher resolutions than say a 3100-3200Cuda core gpu with 6GB VRAM?
     
  8. X71200

    X71200

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    Yes, it's called SLI AA. One card gets dedicated to running AA only while the other renders the scene. You need SLI in order to do it.
     
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  9. RCoon

    RCoon Gaming Moderator Staff Member

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    There is no point in using MSAA on 4K. The higher the PPI, the less need there is for any anti-aliasing whatsoever. If you intend on going 4K, stick to CS or TX or plain old AA.
    MSAA will literally halve your performance.

    SLI AA thanks to X71200:

    http://www.nvidia.com/object/slizone_sliAA_howto2
     
  10. Upgrayedd

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    Ok. so the cards would HAVE to be the same? I couldn't have say a 780 and a 760 with the 760 on AA?
     
  11. CrAsHnBuRnXp

    CrAsHnBuRnXp

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    Am I wrong in assuming that the need for a dedicated PhysX card is pointless as a single 770 should be able to do that and it's original graphic work without issue?
     
  12. Upgrayedd

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    I don't think so. I'm really just trying to learn what exactly all you can do with multiple gpus. Same architecture or not. Same VRAM amount or not. If a dedicated AA card is possible.
     
  13. X71200

    X71200

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    Yes.
     
  14. Upgrayedd

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    Correct me if I am mistaken but can't you have an AMD gpu and a Nvidia gpu in the same system just choosing which one to run or what exactly can be done there?
     
  15. GhostRyder

    GhostRyder

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    Well technically if your talking about like say having an R9 290X and a GTX 780ti in the same system to run games separately you can do that by switching which connector your monitor is plugged into (I believe jokingly linus tech tips on youtube did something like that). Now if your talking about having like an R9 290 and then a GT 740 for PhysX that is only possible if you run a mod program called Hybrid PhysX.

    But generally speaking an AMD card and Nvidia card do not work together in harmony.
     
  16. Upgrayedd

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    My real question is whether or not you can have a dedicated AA card without having the same cards.
    Could I use SLI AA with two different Nvidia gpus? What is it saying by SLI8x and SLI16x in the AA options?

    Thanks for all the helpful answers so far.
     
  17. RCoon

    RCoon Gaming Moderator Staff Member

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    No, you can't. Same GPU only for SLI, that goes for SLI AA.
     
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  18. D007

    D007

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    Better read my topic here before you go 4k sli.
    http://www.techpowerup.com/forums/threads/beware-of-4k-misleading-advertising-and-sli.204582/

    Agreed, you do not need MSAA.
    I use AA x2 and that's it.
    Things look insane.

    This is how 4k looks with AA2x
    I made these videos @4k with 2XAA
    The awesom part is, this is only using ONE gtx 680, not even in sli and I stay above 30fps.
    Any lag you see is due to fraps.



     
    Last edited: Aug 27, 2014

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