Mac Pro Dual Monitor DVI-2 Slow

Discussion in 'Mac Pro' started by subtitles, Jun 23, 2008.

  1. subtitles macrumors newbie

    Joined:
    Jun 23, 2008
    #1
    Hello,

    Since getting my '06 mac pro w/Nvidia 7300 (and later upgrading to the 8800) - performance on DVI-2 is always slow with things like DVD/iTunes. Drag to DVI-1, plays flawlessly...

    I'm sure this has been covered - but is there info/fixes on this issue?
     
  2. SpinThis! macrumors 6502

    Joined:
    Jan 30, 2007
    Location:
    Inside the Machine (Green Bay, WI)
  3. subtitles thread starter macrumors newbie

    Joined:
    Jun 23, 2008
    #3
    Howdy,

    DVI-1 is 1920x1200 24" LG Monitor
    DVI-2 is 1360x768 23" LCD TV using DVI to VGA cable.
     
  4. slughead macrumors 68040

    slughead

    Joined:
    Apr 28, 2004
    #4
    Could be a VGA issue.

    Apple's not been nice to VGA for a while now.

    My only guess...
     
  5. Mackilroy macrumors 68040

    Mackilroy

    Joined:
    Jun 29, 2006
    #5
    Just to chime in here, I've got two 20" displays hooked up to my 8800 GT via DVI, and I don't have any screen lag. Later I'll hook my Pro up to our TV via VGA and drag one of my monitors out there and use DVI and report back with results.
     
  6. hms84 macrumors regular

    Joined:
    Jul 28, 2007
    #6
    I have 7300 GT hooked up to 20" ACD and to my FULL HD SONY DVI-HDMI @ SWEET 1080p ....

    NO LAGS... (^_^)
     
  7. Tallest Skil macrumors P6

    Tallest Skil

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    Aug 13, 2006
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    1 Geostationary Tower Plaza
    #7
    Swap your monitors and see if the problem stays in the same place.
     
  8. subtitles thread starter macrumors newbie

    Joined:
    Jun 23, 2008
    #8
    Thanks for the feedback.

    If I swap displays - the 1920x1200 display on DVI-2 becomes laggy for iTunes/DVD video. 1360x768 on DVI-1 plays smooth.
     
  9. SpinThis! macrumors 6502

    Joined:
    Jan 30, 2007
    Location:
    Inside the Machine (Green Bay, WI)
    #9
    If you unplug DVI 1 (and keep DVI 2 plugged in) what happens? Theoretically DVI 2 should be smooth since it's not using the "bandwidth" from 1 but if it could potentially be a hardware problem if it continues. When you swapped out, did you restart the machine? Theoretically you shouldn't have to but it might reset the driver.

    What does System Profiler display (under Graphics/Displays). Quartz Extreme should show "supported" for both displays...
     
  10. Mackilroy macrumors 68040

    Mackilroy

    Joined:
    Jun 29, 2006
    #10
    Getting back to this... no problems with laggy video or music on my 20" monitor or the 46" HDTV, which is currently hooked up via a DVI-VGA adapter.
     
  11. subtitles thread starter macrumors newbie

    Joined:
    Jun 23, 2008
    #11
    DVI-2 (on its own) appears to be smooth, and Quartz Extreme is supported for both. Thank you again for the support.

    One thing I forget to mention is that iTunes is especially laggy when video is played in its own window on DVI -2 (leaving the iTunes program on DVI-1).

    I've experienced this both the 7300 & 8800. I can smooth things out a bit by keeping the video in iTunes program, and keeping the whole thing maximized on DVI-2.

    Some more information would be when I play HDTV rips I've done via VLC - DVI-1 will play smooth full screen, but will lag badly on DVI-2.
     

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