MSI 7970 OC DisplayPort issue! Any ideas?

Discussion in 'Mac Pro' started by Daze513, Nov 18, 2015.

  1. Daze513 macrumors newbie

    Joined:
    Sep 22, 2015
    #1
    Hey guys, I have a new to me, MSI Radeon HD 7970 OC model. It's a reference style card. I'll include the link below to the specific model. It's flashed on the bios switch #2 for Mac and it works perfect with a single ACDHD 30" via DVI.

    The problem I'm having is that I have since added 2 more ACDHD 23" and I have Mini DisplayPort to DVI adapters for those. Last night I tried plugging in all 3 monitors and one of my MDP is not outputting any video signal. The MDP closest the HDMI is not showing signal to the displays. I swapped the displays and sure enough the problem is not the screens. The DVI is powering the 30" no problem, but then only one MDP works. I unplugged the 30" and tried going only with the 23"s on both MDP and nothing either.

    I plugged in my TV to the HDMI and it only works after unplugging the other 2 MDP.

    Any ideas what can be wrong with the flash or something to not allow output via the MDP closest to HDMI? My idea is basiacally to not use HDMI and power all three DVI monitors via the DVI and 2 MDP.

    Thanks.
     
  2. Fl0r!an macrumors 6502a

    Joined:
    Aug 14, 2007
    #2
    Do you have active mDP adapters? You need at least one of them for 3 concurrent displays (AMD Eyefinity).
     
  3. Daze513 thread starter macrumors newbie

    Joined:
    Sep 22, 2015
    #3
    Ok and I get that. But what about when I plug in just to that particular MDP and I get no signal? Or when I do just both MDP, or DVI and that one particular MDP port?

    Can the port be bad or something? Anything else to test before I call it a bad port? I was thinking maybe it shares a link or something with a different port. IDK just really trying to find a reason why it's not bad.
     
  4. Fl0r!an macrumors 6502a

    Joined:
    Aug 14, 2007
    #4
    You said you swapped the displays, did you also swap the adapters? Maybe one of them is just faulty?
     
  5. Daze513 thread starter macrumors newbie

    Joined:
    Sep 22, 2015
    #6
    Yea I swapped adapters and also tried 2 different brands. And nothing.

    I'm in contact with MacVidCards to see if there is anything maybe he can do if I send him the card but is there any trouble shooting I can do to try to get to the problem before shipping out?
     
  6. Fl0r!an macrumors 6502a

    Joined:
    Aug 14, 2007
    #7
    That's strange, maybe this port is really defective...
    Did you see what happens when booting up with the normal PC BIOS?

    Btw, a DP connector carries both a modern DisplayPort signal as well as a legacy TMDS signal, which is used by passive HDMI/DVI adapters (yours), so using a real DP device or an active adapter will be a completely different story. I'd give this a shot, since you need an active adapter in any case.
     
  7. Daze513 thread starter macrumors newbie

    Joined:
    Sep 22, 2015
    #8
    Yea I already ordered 2 active adapters and get them Friday. But it's just weird to me that even with that one Mini DisplayPort as the only output I get no signal. I really hope it's just a flash or software thing, and not something defective with the card.
     
  8. Fl0r!an macrumors 6502a

    Joined:
    Aug 14, 2007
    #9
    Try booting your Mac with the switch set into PC BIOS position. If it behaves differently, it might be a somehow mismatched Mac EFI ROM (which I don't believe to be honest).
     

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