Mac Pro 5,1 Multiple Video Cards booting/gaming

Discussion in 'Mac Pro' started by Noldat, Sep 26, 2014.

  1. Noldat macrumors newbie

    Joined:
    Sep 18, 2014
    #1
    Hello all,

    I have 2012 Mac Pro and I have a video card question. I apologize if this comes of very newbie :D.

    1. I have a Geforce GTX 660 non flashed that i use right now for gaming, i also have (not installed at the moment) the ATI card that came with machine. Can i run both cards and run my gaming off the Geforce and my second monitor off the ATI so i can actually see the boot screen? Are there any downsides to this?

    2. If this is possible what determines which video card is used for gaming? Is it simply which monitor i have the game displayed on?

    Thanks in Advance
     
  2. Ironjer macrumors regular

    Joined:
    Jul 18, 2013
    #2
    Good question did you try move you monitor to GTX when Windows is running and disable ati?
     
  3. omvs macrumors 6502

    Joined:
    May 15, 2011
    #3
    In OSX, I believe the 'primary' screen gets used for gaming.

    I've run a 4k samsung hooked up to a non-flashed AMD 7950, along with a 27" generic hooked up to a GT120 for bootscreen. Worked fine - I designated the 4k as the primary, and in OSX fullscreen games went ther.

    In windows, you can do something similar - I actually disabled the 27" and had all video go to the 4k -- something not easily doable in OSX. Games were fine.

    Currently I'm using a single flashed GTX680 for both screens, but when i upgrade the video I'll go back to using the GT120 for boot / secondary, and the new card on the 4k screen.
     
  4. Noldat thread starter macrumors newbie

    Joined:
    Sep 18, 2014
    #4
    I actually haven't used this machine for windows at all yet.

    So if i set the GTX as the primary and boot will i see the boot screen on the ATI? My GTX isnt flashed.
     
  5. omvs macrumors 6502

    Joined:
    May 15, 2011
    #5
    During initial boot you'll only see an image on the ATI. Doesn't make a difference what OSX has the the primary set to.

    At some point the OSX drivers kick in, and then both cards will be active as normal. If you're not using file vault, this will be right before the login screen. With filevault password entry occurs before the video drivers are active, so you'd need the ATI card to be able to see what you're doing.


    As far as I know, there's no downsides to this approach other than occupying an extra PCI slot.
     
  6. Noldat thread starter macrumors newbie

    Joined:
    Sep 18, 2014
    #6
    Could their be issues because one is ATI and the other is Nvidia?
     
  7. omvs macrumors 6502

    Joined:
    May 15, 2011
    #7
    I had the reverse mix and it worked fine.

    Oddly enough it might be harder to have both new and old ATI cards - here's a posting on netkas.org about it where the author 'expressed his displeasure' at the amd drivers: http://netkas.org/?p=1322#comments

    I think that was more a windows problem. In past years I've had windows do bad things to me when I moved from a ATI card to a NV card -- system got screwed up enough I had to completely reinstall. These days things might be better, though your ATI card does use a pretty old driver.

    At one point I believe my friend had her old ATI card (same one as yours) along with my GTX680 in the same system, and I think it worked okay. But that was short term testing - now she's using a flashed 7950 as a single card.
     

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