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GTX670 SLI - what am I doing wrong?

Discussion in 'NVIDIA' started by Whitestar, May 2, 2013.

  1. Whitestar New Member

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    I finally bought another 4GB Asus GTX670 card and set it up in SLI. I inserted it in the second PCI-e slot in my P8P67 Deluxe, connected power cables and connected the SLI bridge.

    Booted up and all looks good. Enabled SLI in drivers (314.22). Note! I did a fresh Windows-install after bying and inserting the first 670. I did not re-install drivers after inserting the second card.

    But when I started testing things were not so good. It seems there is no scaling at all, or just slightly. I have seen youtube-videos of people with similar setups, and they have decent scaling.

    Anyway, here are the test results (sorry for slow ImageShack). Unless specified, all test were run at 1920x1080 with AA off and AF @ 16x

    Just Cause 2:
    This is single-GPU with AA 4x. All settings are max, but SSAO, HDshadows and Water emu are off. The usage is almost at 100% and the fps 132.
    [​IMG]

    This is SLI (Alternate Frame Rendering 2) with AA 4x. Almost identical performance here. No wonder, since both GPUs are used only 50%. 0.5 + 0.5 = 1 isn't it? :) I used AFR2 here, because the "nVidia recommended" setting actually produced even lower fps in SLI. AFR1 was abysmal.
    [​IMG]


    Far Cry 3:
    Settings are mostly at medium or high, geometry at ultra. I only have an image of SLI here, but single-GPU yields almost identical performance in this spot. At the base of the nearby antenna, when overlooking the village, I get 83 in single and 93 in SLI. So a slight increase in that one spot, but far from what I expected.
    [​IMG]


    Skyrim: Yeah I know this game sometimes has negative SLI scaling, but I'm giving an image here anyway, since it follows the trend from other games. Even in one of the most demanding spots (on top of stairs at Dragonsreach) it has exacly the same fps with or without SLI. Image is of SLI. At most demanding spot in Markarth I also get about the same fps with or without SLI, around 46-50.
    [​IMG]


    Crysis benchmark:
    I set all settings to Gamer and ran the standard GPU benchmark of the vanilla game. Here are the results:
    SLI:
    Play Time: 21.79s, Average FPS: 91.76
    Min FPS: 57.58 at frame 197, Max FPS: 120.45 at frame 148

    Single-GPU:
    Play Time: 22.29s, Average FPS: 89.73
    Min FPS: 51.47 at frame 178, Max FPS: 114.76 at frame 1651


    In every game I made sure that "Prefer maximum performance" was enabled. And of course selected Single-GPU, AFR2 or nVidia Recommended (SLI) depending on what I was testing.

    So does anyone have a clue what is happening here? One should almost thing that my CPU is limiting the cards, but surely that can't be the case when running at 4.4GHz (well, apart from Skyrim I guess)? Also, I have read reviews and seen youtube videos where they get decent scaling when using a setup similar to mine. The funny thing is that the usage seems to increase when the burden is light (less demanding scenario). But where the games are GPU demanding the usage seems to get reduced, usually to around 50%.

    Is it a driver issue? Should I reinstall the driver or perhaps try the new 320 driver?
    I need some help here, or this might turn out to be the worst investment I have ever made. :shadedshu

    Sorry for long post. :)

    Edit: I forgot to mention that Unigine Heaven seems to scale nicely. I get 63 fps with single-GPU and 117 in SLI. Is the SLI scaling really that bad in the other games?
    Last edited: May 2, 2013
  2. FreedomEclipse

    FreedomEclipse ~Technological Technocrat~

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    random question - did you remember to add the SLi bridge?
  3. Whitestar New Member

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    Read the second sentence in my post. :)

    But yes, I connected it and in NVCP it says SLI enabled, and there is a green thick line that covers both cards in the image. So I'm assuming it's working as it should.
  4. BarbaricSoul

    BarbaricSoul

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    so your not getting any FPS increase from the second card?
    Crunching for Team TPU 1 Million points folded for TPU
  5. Whitestar New Member

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    Yes, in the Unigine Heaven bench, but in the games it's marginal at best it seems.
  6. centaurius

    centaurius

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    Download MSI Afterburner and check after playing some if you see any GPU2 usage. (GPU1 should be 99% in farcry3 or skyrim). Just confirm if you having SLI enabled the GPU2 has some usage or not.
  7. Whitestar New Member

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    Not sure what you mean. Did you see the two JC2 screenshots? In SLI both GPUs are at about 50% and in Single-GPU the active card is almost 100% and the other 3%. Tested using EVGA Precision X. Are you saying it can report false usage and I should try Afterburner instead?
  8. centaurius

    centaurius

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    Hmmm...

    You have "prefer maixum performance" instead of "adaptive power" in global settings? And you use Vsync "FORCE OFF" ?

    If so, try to disable hyperthreading in BIOS, so u only use 4 cores/4 threads instead of 4/8 (as default on i7). Dont OC the i7, see how it goes without OC first and if you see more usage on both GPU's you can start OC. And your BIOS version of motherboard is up to date?
  9. ruff0r

    ruff0r

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    Random question #2 have you inserted the second card in the black pci-e slot?
  10. Whitestar New Member

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    It seems SLI is working correctly after all. Just isn't working to well in those games. They are probably a bit CPU limited. I ran Unigine Heaven and that doubles performance in SLI. Also I just installed the latest 320.14 beta drivers and they double my framerate in Trackmania2 Canyon and Trackmania2 Stadium. So I suppose everything is in order. Thanks for helping out anyway. :)

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