Resolved Boot screen question

Discussion in 'Mac Pro' started by mattspace, Nov 12, 2017.

  1. mattspace macrumors 6502a

    mattspace

    Joined:
    Jun 5, 2013
    Location:
    Australia
    #1
    This might be a self-evident question, but if I wanted to go down the road of putting a non-efi GPU in my cMP, like a 1080ti and power mod, and keep the GT-120 for boot screens, how does the system know which screen / card to direct the boot screen towards?

    Does it just always go to the efi card, or do you have to keep the efi card in slot 1 etc?
     
  2. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    Boot screen always only available on the GT120 in this card, regardless which slot you put it in. In your case, usually put the 1080 in slot 1 and GT120 in slot 3 or 4.

    Anyway, there is no need to perform any power mod for 1080.
     
  3. mattspace thread starter macrumors 6502a

    mattspace

    Joined:
    Jun 5, 2013
    Location:
    Australia
    #3
    ahh cool, so the boot screen will always show up on the efi card, regardless of the slot it's in?
     
  4. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #4
    Correct, but AFAIK, no boot screen for 4k 60Hz on GT120 (anything up to 1440P is fine). So the monitor itself can also make the difference. Anyway, as long as you set the DP version to 1.1 On the monitor side, boot screen should always available.
     
  5. murnau macrumors newbie

    murnau

    Joined:
    Oct 21, 2017
    Location:
    Bulgaria
    #5
    That is part of a question I also have - when I have 2 GPUs
    One for the boot screen and one for after.
    How do I change in the OS X after booting?
    Or I just remove the video cable of the monitor and move it to the other card and this enables the second GPU?
     
  6. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #6
  7. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #7
    May be a simple cheap display port mechanical switch can do the job.

    Pull the cable is one of the option, but I don't think it's a good idea to do that everyday, or even few times per day.

    Some monitor has multiple input, you may use the monitor input selector as a solution. However, the Mac will consider you are connecting to 2 monitors. You can choose the mirror option to avoid the mouse cursor going to the "offline" monitor, but I am not sure if the GT120 will affect the overall system performance in this case.

    With a switch, you can easily switch the online / offline GPU. The system won't consider you are running multiple display, and you can put the switch right next to you, no need to reach the back of the Mac Pro. And less chance to induce any damage (pulling a cable that is transmitting usually is not a good idea.

    My bad, I misread that. Thanks for pointing that out. However, 1080Ti is virtually the same situation.

    I am running a 1080Ti right now. I can confirm that CUDA-Z heavy test can cause issue. However, that seems to be a very exceptional case. Even MVC page stated that, the power draw of the 1080Ti is generally lower than the 980Ti, and the 980Ti can run with just the mini 6pin.

    I can run everything including Furmark (and OCCT in Windows) without any issue. And obviously the power draw for real world usage is not a problem at all. I tested it in both MacOS and Windows.
    1080Ti power draw.jpg
    So, unless OP get a factory OC 1080Ti. Or his daily job is to run CUDA-Z heavy test. IMO, there is no need to go through the pixlas mod. But of course, if he doesn't mind to do that, I totally agree that let the 1080Ti drawing power directly from the PSU is better than via those tiny mini 6pin ports.

    Anyway, even if don't want to go Pixlas mod, and worry about the power draw, as MVC said, a simple SATA to 6pin cable can also alleviate the problem. Not really need an external power.
     
  8. murnau macrumors newbie

    murnau

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    Oct 21, 2017
    Location:
    Bulgaria
    #8
    Thanx, but what switch? Could you give me details please?
     
  9. h9826790 macrumors 604

    h9826790

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    Apr 3, 2014
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    #9
  10. DenBeke macrumors regular

    Joined:
    Aug 11, 2011
    Location:
    Antwerp
    #10
    Depends on how much you need the bootscreen?
    Why would you need it every day? Just only in case something goes wrong you want to have the EFI card.
     
  11. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #11
    I totally agree boot screen is completely useless in day to day work. I have more than one Mac EFI GPU, they are all inside the paper box now.
     
  12. murnau macrumors newbie

    murnau

    Joined:
    Oct 21, 2017
    Location:
    Bulgaria
    #12
    Thanx for the reply, h9826790!
    I use it a lot, the bootscreen, I navigate between WIndows and mac OS and I make install disks also for people...

    I want to buy a PC card 6870 for my mac pro 2.1 and wanted to have the bootscreen but since I am not sure if I will be able to flash it correctly, I was inquiring about the possibility to switch between GPUs hence my question.
     

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