Iris graphics for external monitor (dual graphics)

Discussion in 'MacBook Pro' started by bonro001, Aug 23, 2014.

  1. bonro001 macrumors newbie

    Joined:
    Jan 14, 2014
    #1
    Hello all. I have a Mid 2014 MBP with dual graphics cards. I want to see if maybe the Iris graphics might be faster at some tasks while hooked to a external monitor. Is there a way to do this? (I know the units with a single GPU can drive external monitors, but with dual it seems to only be allowed while using the 750M)

    Thanks!
     
  2. MagicBoy macrumors 68040

    MagicBoy

    Joined:
    May 28, 2006
    Location:
    Manchester, UK
    #2
    Using an external display automatically uses the dGPU.

    No option to override it.
     
  3. bonro001 thread starter macrumors newbie

    Joined:
    Jan 14, 2014
    #3
    Thank you, sadness. Have been reading a ton about how good the Intel graphics are, curious if it would be better in gaming.
     
  4. MagicBoy macrumors 68040

    MagicBoy

    Joined:
    May 28, 2006
    Location:
    Manchester, UK
    #4
    Generally speaking the 750M is usually around 25% quicker than the Iris Pro.
     
  5. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #5
    The 750M is still way better in gaming.

    But the Iris Pro works better in OpenCL tasks.

    And on models withe the 750M, the Iris Pro isn't physically connected to the Thunderbolt port, so the 750M has to be used when driving external displays.
     
  6. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #6
    You can't use the iGPU on an external monitor. Its dGPU is hard wired and there's no way around it.

    the dGPU is still better then the Iris Pro, especially at games.
     
  7. x3n0n1c macrumors regular

    Joined:
    Jul 9, 2014
    #7
    In gaming the difference is usually closer to a 75-100% speed increase over the Iris Pro.

    Just as an example, in CineBench r15 I get 32-33fps with the Iris Pro and 60 FPS with the 750m. In Unigine Valley its ~15 FPS vs ~25 FPS.
     
  8. MagicBoy macrumors 68040

    MagicBoy

    Joined:
    May 28, 2006
    Location:
    Manchester, UK
    #8
    Source?

    I was looking at barefeats.
     
  9. x3n0n1c macrumors regular

    Joined:
    Jul 9, 2014
    #9
    My actual results from my laptop, they aren't from a third party.
     

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