Monitor Input issue

Discussion in 'Mac Pro' started by PitBullCH, May 14, 2015.

  1. PitBullCH macrumors newbie

    Joined:
    May 14, 2015
    #1
    Greetings,

    I have a MacPro 3.1 (Early 2008) with 64GB RAM, 2x 3.2GB Quad Xeon CPUs, and an EVGA nVidia 680 Mac Edition GPU - O/S is fully patched to latest Yosemite.

    The GPU has DP, HDMI and DVI-D outputs, and historically this was connected via DVI-D to an old (circa 2008) BenQ 1920x1080 monitor - worked well enough but recently the itch started for a 4K monitor...

    So I bought an LG 31MU97 monitor - this has DP, miniDP and 2x HDMI inputs, and currently I am using it at 4096x2160x50Hz using DP-DP connection.

    This works fine most of the time - and after i1Profiler calibration it's actually a very nice display (although the monitor controls via the little joystick suck and the OSD is painfully slow).

    However when I boot the system it never sees the DP connection and won't boot - I have to connect an HDMI cable and switch to HDMI input to have it boot and then I can switch back to DP - although sometimes it still doesn't see DP and I then have to faff around with multiple displays in the Displays Sys Prefs and then disconnect the HDMI. Very irritating.

    Same issue with DP-miniDP.

    Any thoughts on what to try to resolve this ?

    Regards.

    PitBull (in Switzerland)
     
  2. mikeboss macrumors 65816

    mikeboss

    Joined:
    Aug 13, 2009
    Location:
    switzerland
    #2
  3. PitBullCH thread starter macrumors newbie

    Joined:
    May 14, 2015
    #3
    Hi Mike - thanks for that response.

    Do you know if this is also an issue with other cards or just the 680 ? I was hoping to get a Titan X from MacVidCards (when they get some stock in)...
     
  4. nigelbb macrumors 6502a

    Joined:
    Dec 22, 2012
    #4
    Does it boot OK if you have a second monitor connected to one of the HDMI ports?
     
  5. mikeboss macrumors 65816

    mikeboss

    Joined:
    Aug 13, 2009
    Location:
    switzerland
    #5
    I don't know. I returned the 4K display after fiddling with it for a few days...
     
  6. PitBullCH thread starter macrumors newbie

    Joined:
    May 14, 2015
    #6
    It boots fine with just HDMI, or with HDMI and DP to the same monitor (haven't tried with 2 monitors).
     
  7. ilandmac, May 23, 2015
    Last edited: May 23, 2015

    ilandmac macrumors member

    ilandmac

    Joined:
    Mar 25, 2012
    Location:
    Remote island
    #7
    I have sort of the same issue.

    Running a MacPro early 2008 flashed, with Radeon HD7950. Mavericks 10.9.5

    Booting with both Apple Led display & 31MU97 connected to display port boots to the Apple screen.

    The only way that I can boot with the LG screen alone is to add an HDMI connection. It will boot on that then I have to select the display port from
    the LG menu. The screen will come up greyed out with nothing on the desktop.

    Unplugging the HDMI connector brings things back to normal.

    The thing is, once you've tasted the display port's 60 hertz there's no going back to the 30 hertz of HDMI...

    Tedious.
     
  8. PitBullCH thread starter macrumors newbie

    Joined:
    May 14, 2015
    #8
    Just as an update - I never did get the EVGA 680 to boot with just a DP cable - so had to leave HDMI cable connected.

    I've since replaced it with a Titan X from MacVidCards - happy to say that this boots up normally with a DP cable (or HDMI) and works fine.
     

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