Video lags on 2nd monitor with HD7970

Discussion in 'Videocards - AMD Radeon' started by skoolz, Aug 2, 2012.

  1. skoolz

    skoolz Active Member

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    GPU:
    GTX 980 G1 x2 (SLI)
    I have my 7970 hooked up to my monitor via DVI and my Sony Bravia HDTV via HDMI. When I run them both as duplicated or just run a single monitor, video runs fine with no hiccups. However, when I use "extended desktop" mode, any video I slide over to the TV loses framerate to the point that it is noticeably laggy when in full screen. This lag has occurred using VLC and even flash video online when full screened. Has anybody else experienced this or know what's going on? Card tests fine with games and benchmarks when on a single monitor.

    (PS. I'm using Catalyst 12.7 beta, but the same thing occurs with the official 12.6)
     
  2. BrightCandle

    BrightCandle Active Member

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    GPU:
    MIS / 680 / 2GB SLI
    Yes I noticed this problem. The issue is that the cards don't run at appropriate clock speeds to drive the second monitor quickly enough and so the card physically doesn't keep up with the demands on it, causing lag and low frame rates. It gets worse the more screens you add on.

    If you force the card to its highest clocks the problem will mostly go away. I think its mostly a problem with the power saving algorithm not being appropriate for multiscreen users but I suspect its also a core performance problem in supporting Windows because GPU-Z never showed any appreciable GPU usage.
     
  3. Mufflore

    Mufflore Ancient Guru

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    GPU:
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    Disable desktop composition in the video players shortcut (compatibility tab), this will free up an overlay for video.
     
  4. skoolz

    skoolz Active Member

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    GPU:
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    Can someone elaborate on this? I'm very interested in this fix, how it's done, and what cons will I encounter?
     

  5. Mufflore

    Mufflore Ancient Guru

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    It will turn Aero off while the video player is running.
     

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