rMBP 15" 2014 battery drain under high load

Discussion in 'MacBook Pro' started by HunPro, Mar 24, 2015.

  1. HunPro, Mar 24, 2015
    Last edited by a moderator: Mar 24, 2015

    HunPro macrumors member

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    Budapest, Hungary
    #1
    Hi!

    I've heard about the throttling issues 15" Retina MacBook Pro owners had since 2012.

    I wasn't expecting anything similar, as mine is a Retina MacBook Pro 2014, i7 2.2 GHz with Iris Pro. This one has the same cooling system that the dedicated nVidia graphics versions have, and the same 85W power supply, but it only has to take care of the Core i7 -477HQ CPU, with a max TDP of 47W.

    However, while stress testing it with Civilization V, I noticed, that after one and a half hour the battery begins to drain, (the MagSafe chargers led turns orange).

    Since the total power consumption of this system is lower, as it has no dedicated GPU, I wonder if my case is common?

    Based on this there's no safe version of the 15" MacBook Pro for power users, as even the base models can't be run sustainably, and higher-end models add a cca. 40W GeForce chip as well.
     
  2. HunPro thread starter macrumors member

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    #2
    One tool I'll try

    and probably recommend to anyone.

    It's called "Turbo Boost Switcher". It enables you to turn Turbo Boost on and off. I used version 1.0, there should be 1.2, but you may need to contact the developer.

    It will prompt you for superuser access, as it messes with kexts on the fly.

    Here are the test results, using Intel's own app, Power Gadget:

    [​IMG]

    • At first, normal usage.
    • Then I turn off Turbo Boost.
    • Then I launch a 4K video in Chrome (google "4k youtube")
    • You can see that it tops out at 2.2 GHz
    • Then I turn Turbo Boost back on
    • You can see it going up

    Now Turbo Boost is great for normal usage: your machine is snappier, you have "race to sleep", lower clock speeds, all the benefits.

    But when you have to put constant stress on the CPU, giving it a job it can never finish (Civilization V), it will just work itself to death.

    You'll run into one of these:

    • thermal limits: Iris Pro and the 4 cores are on the same die, competing for resources . Running the 4 cores lower allows greater thermal headroom for the GPU.
    • thermal throttling: the cooling system reaches its limits, and performance can suffer
    • power limits: Iris Pro and the 4 cores are on the same die, competing for resources . Running the 4 cores lower allows greater energy use for GPU.
    • power limits: the power supply can't provide enough power, and the machine starts to use the battery. You're not only putting wear on the battery, but also enter a state that is unsustainable: the battery will run out

    Since this is a DTR machine, I believe that it's crucial for it to be able to handle extended periods of heavy use, when connected to a power supply.

    I will test tonight if I can get the same behaviour with Turbo Boost disabled.
     

    Attached Files:

  3. Samuelsan2001 macrumors 603

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    Oct 24, 2013
    #3
    It isn't bypassing the battery

    It is just draining the battery faster than power supply can charge it at full levels. As you may have noticed the more charge a battery has the longer it takes for those last few percent to fill.

    When really pushing the machine the drain is just faster than this final bit of charging is if you leave it it'll eventually equal out.
     
  4. HunPro thread starter macrumors member

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    Budapest, Hungary
    #4
    No, the battery is not used when you're plugged in by default. It is only used when the power adaptor's input (85W) is exceeded under heavy load.

    The first results are promising:

    [​IMG]

    I pinched in an out for the desktop, while playing a 4K video.

    The disabled phase is clearly visible.

    Note how the power usage stays at 47W without turbo, but goes up to almost 70W with it.
     

    Attached Files:

  5. Samuelsan2001 macrumors 603

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    Oct 24, 2013
    #5
    I stand corrected

    I don't see it as an issue if you are sat there playing starcraft for long enough to drain your battery you probably should have bought a gaming desktop...
     
  6. HunPro thread starter macrumors member

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    #6
    This topic is not for you then.
     
  7. HunPro thread starter macrumors member

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    #7
    Success

    It seems that disabling Turbo Boost did the trick: while the GPU still used turbo, and the "package" power consumption reached 60W, the battery wasn't draining.

    Next stop: limiting the GPU turbo.
     
  8. xiwong macrumors member

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    Dec 9, 2013
    #8
    This is an interesting topic, because on my 2012 cMBP I can't get it to drain the battery anymore under load. As some other users realized, sometime during the Mavericks era there was an update that put a hard power draw cap at around 80W and now the thing just throttles. Personally I wish it would just drain the battery, because I can get it to throttle both CPU and GPU quite easily without even close to full load on both.

    I don't know what they were thinking when they put a 45W TDP CPU and a 45W TDP GPU (not even considering all the other power hungry components) in a computer with only a 85W PSU.
     
  9. simonsi macrumors 601

    simonsi

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    Auckland
    #9
    Apple don't consider them PSUs as you would a desktop, hence Apple referring to them en masse as "Charging Devices". Their not unreasonable view is that if you want a machine to run that hard continuously then the target device isn't a Macbook Pro, its just part of their tradeoff of function vs portability.

    Its widely known that the chargers can't cope with the full demands of the machine at full load, most MBPs will immediately throttle the CPU if the battery is removed and you boot on just the Power Adapter for exactly that reason.
     
  10. xiwong macrumors member

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    Dec 9, 2013
    #10
    Definitely agree with you here. I guess in my past two years of ownership I've outgrown the market Apple provides, which is OK.

    But then again, looking at designs like the Razer Blade's power adapter (which doesn't take up that much more volume, but is 150W), I know it is possible for Apple to put in more wattage (maybe 120W) in a similar profile as the current adapter. That would solve the majority of the performance issues I have right now.
     
  11. simonsi macrumors 601

    simonsi

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    #11
    Yes as I posted I was thinking how feasible it would be to <simply> release a 100-120W power adapter to resolve this but I think it may have more to do with market/range positioning...?
     
  12. HunPro thread starter macrumors member

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    Budapest, Hungary
    #12
    My MacBook Air (2011, 17W Core i5) wasn't running into this problem, because the power adaptor was powerful enough. I could torture that thing with Hearts of Iron III for hours and hours.

    Shipping a larger power adaptor, let's say a 100W one shouldn't be a problem, as the new and tiny USB port (3.1? I'm always confused) can supply 100W, so a dedicated, gold plated MagSafe connection should also be able to handle this.

    Anyway, disabling the Turbo Boost on the CPU solved my problem, I've just ran Civilization V for 3+ hours.

    It stays around 90-91 C, and 5000-5200 rpm on both fans, but it's stable. With fan control I could keep it cooler, but I'm fine with this temperature range. Ever since the Pentium IV era, Intel chips have been running this hot without any major failure or recall, unlike dedicated graphics chips from AMD/nVidia.

    I would gladly disable the turbo on the GPU as well, but I couldn't find a solution. If I had any experience with OS X app development, I would look into the source code of the Turbo Boost disabler, and figure out something, but I'll just stick to my own field for now.

    And again: since the GPU still uses turbo, power consumption can exceed 47 W, even in this mode. Somehow it seems that it tries to hover around 47 W, but it can jump up to 60 W from time to time.
     
  13. lzbones macrumors newbie

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    Nov 13, 2010
    #13

    What was the temperature of your CPU when playing Civ5 with turbo on? My 2.5G CPU was around 95 to 100 C with Civ5.
     
  14. HunPro thread starter macrumors member

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    #14
    Just as I wrote: 90-91 C, ambient around 20-22 C
     

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