rMBP unable to charge fast enough under intense load?

Discussion in 'MacBook Pro' started by randomnut, Sep 4, 2012.

  1. randomnut macrumors member

    Aug 17, 2011
    Last night I sat down for a 3 hour session in Guild Wars 2 on my rMBP. I'm using bootcamp windows 7 with the current drivers, including the most up do date gfx driver from the nvidia site.

    I have the settings cranked up pretty high, so during gameplay the fans are on full pelt and the keyboard seems to be close to melting.

    The battery started off at full, and I had the machine plugged into the charger the entire time, but I found when I finished playing the battery was nearly empty. I am certain the charger never came out and left the slot the entire time.

    Is the rMBP unable to charge fast enough to cope when it is under full load? If so this is a hideous design flaw, and makes this machine simply not fit for purpose if you have no choice but to shut down after a period of running the thing at max load?

    I will test again later and see if it is a continual problem, but just wanted to see if anyone is experiencing this also.
  2. It's Electric macrumors member

    Oct 27, 2011
  3. weemanpow3 macrumors 6502


    Mar 14, 2008
    Guild Wars 2 is an hardware intensive game thus far. Still need some optimization.

    I have 2012 cMBP 2.6GHz and I measured the power it was using playing GW2 and was spiking above 90 watts. The battery would drain to 95% from 100% within 10 minutes but then quickly charge back up.

    A quick fix I did was install ThrottleStop 5.00 and disable Turbo Mode. Between 2.6GHz and 3.4GHz I didn't notice to much performance hit, but It made my laptop a lot cooler and seemed to not drain the battery as quick when plugged in.

    If that doesn't work, your battery drain issue is probably due to the GPU being clock really high by default and the higher res screen.
  4. randomnut thread starter macrumors member

    Aug 17, 2011
    @ It's electric It absolutely was not. Currently testing it right now and it looks like it's happening again.

    I'm probably going to call Apple soon to claim under warranty but I am interested to know if other people are seeing this then i'll simply go for a refund rather than replacement.
  5. mattonthemoon macrumors regular


    Feb 25, 2007
    Toronto, ON
    This is normal under heavy load.

    I asked this same question back in June:
  6. randomnut thread starter macrumors member

    Aug 17, 2011
    Wow, thanks for pointing that out.

    What an absolutely hideous, immense design flaw. I am stunned they think that that was in any way a good idea.

    I know Apple often go for form over function but allowing a machine to be plugged into AC Power and STILL not have enough power run the machine at max is inexcusable.

    Seriously, they advertise this machine as amongst other things being good for gaming and video editing. Say for example, I was to do some video editing, transcoding, or whatever. Something that would have the machine running at max for a period of time which could easily be 12 hours or more. This machine will then have no option but to draw from battery, and then I guess once depleted start scaling back performance until it gets to the level this magsafe can provide?

    This is absolutely shameful. They really ought to have some huge, visible warnings when buying this machine that the AC power is woefully ill equipped to power the tasks this machine is advertised for.
  7. phyrexia macrumors 6502a

    Sep 3, 2010
    Go back to middle school and do some math. :mad:

    rMBP draws more than 85W at max load. This is normal, even happens with my 17".


    Don't get so worked up. It is standard practice across the industry. If you had evaluated the system specifications more carefully you would have noticed the power discrepancy. "absolutely shameful" LOL. Maintain a tighter grip on reality, man.
  8. Lord Appleseed macrumors 6502a

    Lord Appleseed

    Nov 7, 2010
    Apple Manor
    I dont have that problem. I can play Skyrim, Mass Effect 3 or Ghost Recon for several hours and do not end up with less charge that I started with.
  9. randomnut thread starter macrumors member

    Aug 17, 2011
    Standard practice in the industry? I've never had a laptop that could not be powered by mains under full load. But then again I guess most other vendors don't simply try and cut corners for the sake of 'design' and hope nobody will notice.

    If the machine draws more than 85W at full load, then the power supply should provide more than 85W to compensate.

    Nowhere on their specs page does it say that this machine draws more than its power supply can provide, therefore you'll only get the stated power for a brief time before it has no option to drain the battery and start underclocking itself.

    For a machine that is advertised as ideal for high end gaming/video editing and the like, heavily loaded with cpu/gpu specs etc it's pretty shambolic that it can't keep it up for that long connected to mains power. You would expect that be the one place you can guarantee performance :rolleyes:
  10. heisenberg123 macrumors 603


    Oct 31, 2010
    Hamilton, Ontario
    ive actually never heard this about MBPs, not to say ive never heard they work for gaming but they are far from built for gaming
  11. It's Electric macrumors member

    Oct 27, 2011
    What math did you do? But since you like math so much, here you go.

    This review finds that the rMBP uses 82.3 watts on average under heavy load in Windows. Let's suppose that Guild Wars 2 somehow manages to add 15 watts to this consumption, which is highly unlikely. Then the rMBP is using 97.3 watts on average.

    It gets 85 watts from the wall and thus is at a deficit of 12.3 watts. Given a fully charged 95 watt-hour battery, the laptop would be able to run at least 7.5 hours, or more than twice the length reported above. In fact, the rMBP would have to be using over 115 watts on average to drain the battery in three hours.
  12. DrJohnZoidberg macrumors member

    Mar 16, 2012
    A couple of years ago the power supplies that Dell specified with some of their higher-end notebooks were so underrated that the notebooks' CPU was throttled down when the power supply was connected. The power supplies couldn't even provide enough power to run the notebook at moderate load, be grateful that this issue is only evident on your MBP in an extreme case.
  13. yusukeaoki macrumors 68030


    Mar 22, 2011
    Tokyo, Japan
    Does same thing under extreme load with 2011 MBP.

    Running FCPX, iMovie, Aperture, and encoding them will start eating your battery.

    After 30min it went down to 96% with red charging light.
  14. GGJstudios macrumors Westmere


    May 16, 2008
    As already pointed out, it is normal for your MBP to draw power from both AC and battery during periods of extreme demand, such as gaming or other multimedia operations. This can cause your battery to stop charging or even drain, even though it's plugged in. Read the AC POWER section of the following link. This should answer most, if not all, of your battery/charging questions:

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