Is it okay to have the dgpu always on?

Discussion in 'MacBook Pro' started by dk808, Jan 15, 2017.

  1. dk808 macrumors 6502a

    Joined:
    May 13, 2015
    #1
    So having the mbp plugged in to an external display or in bootcamp always has the dgpu on. It makes the mbp a little warmer/hot if running more intensive things but never too hot. I was wondering if this is bad for the laptop to have the dgpu always running. Im not worried about battery life because its always plugged in but other than that is there anything else to worry about? I have the radeon 460 gpu
     
  2. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #2
    There's no harm.

    I used my 2012 rMBP extensively while hooked up on an external monitor, which required the dGPU. That puppy is still going strong and shows no signs of letting up.
     
  3. dk808 thread starter macrumors 6502a

    Joined:
    May 13, 2015
    #3
    Thank you!
     
  4. andreyush macrumors 6502

    andreyush

    Joined:
    Oct 24, 2015
    #4

    What are your temps most of the time ? :)
     
  5. maflynn Moderator

    maflynn

    Staff Member

    Joined:
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    Location:
    Boston
    #5
    I can't tell you anymore. I've moved on to an iMac and my kids use the rMBP. The temps weren't high, perhaps in the the 30s if memory served me
     
  6. keviig macrumors 6502

    Joined:
    Jun 7, 2012
    #6
    My 2016 15" MBP idles at roughly 60c with the dGPU active and connected to a 4k monitor at 60hz. The dGPU puts an additional 10w of heat into the system when driving 2 monitors, so high idle temps are to be expected.
     
  7. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #7
    My MPB never ran that warm, It could get into the 50s under light usage but I don't think I saw it idling in the 60s. I think my MBP ran fairly cool compared to the 2015 modes which I saw people complaining about how warm they were.
     
  8. keviig macrumors 6502

    Joined:
    Jun 7, 2012
    #8
    Yeah I find it a bit strange too. I suspect the Radeon 450 dGPU isn't downclocking properly.
    10W power draw during idle is too much for a GPU that uses just over 20W under full load.
    Might be down to the same flaw that plagues Nvidia desktop GPU's, where if you have multiple displays connected it will stay at high clocks and never downclock.

    If I run just the one monitor (4k) with the internal screen off it consumes a mere 4W, with idle temps dropping accordingly. It seems odd that an additional 62,5% pixels (8 million vs 13 million) would cause an increase in dGPU power usage of 150% (4W vs 10W).
     
  9. WhiteWhaleHolyGrail macrumors 6502a

    WhiteWhaleHolyGrail

    Joined:
    Nov 14, 2016
    #9
    On the 2016, is it simply a case of disabling graphic switching to force the DGPU to run all the time?

    I am considering this as my needs veer more towards power than battery efficiency.
     
  10. keviig macrumors 6502

    Joined:
    Jun 7, 2012
    #10
    Yeah, just go into power saving settings and disable automatic switching. Should stay with the dGPU all the time then. It will run hotter and might make some more fan noise though. It also hurts max CPU performance, as it hits thermal throttling sooner. Sustained CPU speed with iGPU is roughly 3.05-3.1 GHz with fans at 4000 rpm. With the dGPU activated it settles at roughly 2.7-2.8 GH and fans at 5000 rpm.
     

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