4 hrs battery life with dGPU

Discussion in 'MacBook Pro' started by SpecG, Nov 17, 2016.

  1. SpecG macrumors newbie

    Joined:
    Nov 6, 2014
    #1
    Using an external monitor I'm seeing less than 4 hours on the 15 inch, 455, 2.7, regardless of activity. Even just one tab open on Safari results in this. All indexing has been completed. Seems Apple's claimed 10 hours only applies to integrated 530 graphics. If the dGPU kicks in, expect that to drop by 50 - 75%.
     
  2. smelly cat macrumors regular

    smelly cat

    Joined:
    Apr 17, 2010
    #2
    That seems to be in line with what I would personally expect. I think most people have access to their power adapter when they plug in their external monitor, so this shouldn't be a huge issue, no?
     
  3. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #3
    This has always been the case with an external monitor connected. What's the issue?
     
  4. dk808 macrumors 6502a

    Joined:
    May 13, 2015
    #4
    Who the hell is connected to an external monitor while not being plugged in charging though?
     
  5. leman macrumors 604

    Joined:
    Oct 14, 2008
    #5
    If you are using an external monitor, you can also use the charger. I don't see a problem.
     
  6. SpecG thread starter macrumors newbie

    Joined:
    Nov 6, 2014
    #6
    Not an issue necessarily, just a datapoint. I was seeing 7 hours plus when attached to an external monitor with a 12 inch MacBook.
     
  7. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #7
    Massive difference in gpu power consumption hence the difference
     
  8. CE3 macrumors 6502a

    Joined:
    Nov 26, 2014
    #8
    No different on my 2015 model. Integrated graphics and light work = respectable battery life (6-8+ hours)

    AdobeCC Programs/ FCPX / Ableton / Logic / Any big program that uses a lot of resources and dGPU = 2-4 hours
     
  9. SpecG thread starter macrumors newbie

    Joined:
    Nov 6, 2014
    #9
    Understood. Being used to the one port scenario I was surprised to see a meagre 1440p monitor bring down the battery life so much.

    Guess dGPU is anavoidable with anything attached. Leaves you wondering how the MacBook m5 does it without an issue though...
     
  10. leman macrumors 604

    Joined:
    Oct 14, 2008
    #10
    Power management plays a large role. I would imagine that the dGPU is configured with performance scenarios in mind, so if it kicks in, the power draw will be substantial. Besides, the VRAM requires a lot of power to run. And the reason why the dGPU kicks in with external monitors is because external video output is wired through the dGPU (AFAIK the iGPU can't output external video directly on these MBPs).

    The MacBook behaves differently because it doesn't really care about how many monitors are being connected. The iGPU just needs to draw a bit more stuff, usually its neglectable. Most of the time, only a small fraction of the screen needs to be redrawn and modern OSes are fairly good at optimising this procedure.
     

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