Battery life on 11" MBA: 1.4GHz Vs 1.6GHz - what's the likely difference?

Discussion in 'MacBook Air' started by Jobsian, Oct 22, 2010.

  1. Jobsian macrumors 6502a


    Jul 30, 2009
    Add me to the 11" love-in, these are fine machines, and it will be my primary computer. I would ideally loved to have seen 32nm Sandy Bridge, USB 3.0 and integrated 3G/Lte in a product this mobile but I digress.

    I'm seriously considering the 1.6GHz and my question is how much worse is the battery going to be than the 1.4GHz version? And what factors might play a part, eg will they both idle at their max speeds? Etc

    Very impressed by reports of the 5-hour (and beyond, someone got over 6 hours browsing at 40% brightness!) battery. However I haven't seen any reviews/tests on the 1.6GHz battery yet.
  2. cleric macrumors 6502a


    Jun 7, 2008
    Minneapolis, MN
    Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7)

    They're identical wattage aren't they?
  3. Jobsian thread starter macrumors 6502a


    Jul 30, 2009
    I don't know. Does running a processor at 1.6GHz take no more power than running it at 1.4GHz? It seems counter-intuitive. I'm not being facetious, I genuinely don't know.
  4. jagger27 macrumors member

    Feb 16, 2010
    The likely difference is, give or take, a 10% performance bump in CPU intensive tasks. The real difference is added heat, and therefore, more power draw. They have the same max TDP, but I don't think the lower end chip runs as close to the maximum of 10 watts as the 1.6GHz chip does.

    Most tasks would benefit from extra RAM, not CPU. OS X likes to allocate RAM, so doubling it would make it really happy.

    For reference:
    1.4GHz (SU9400)
    1.6GHz (SU9600)

    See for more detail.
  5. alust2013 macrumors 601


    Feb 6, 2010
    On the fence
    It does take ever so slightly more power, but 200MHz will not make any noticeable difference, especially with chips that are already such low power. I'm not sure if those CPUs do this, but I know my computer will actually underclock itself to 1.6GHz if it is idle or not doing much. So those chips may actually underclock to 1GHz or so when not being stressed.
  6. Jobsian thread starter macrumors 6502a


    Jul 30, 2009
    Now with the 1.6 shipping, any updates? I haven't seen any yet personally
  7. Pressure macrumors 68040


    May 30, 2006
    A faster processor doesn't necessarily mean lower battery life.

    The faster the processor, the quicker it will go to the lower power states because it finishes tasks faster. Simple as that.

    AnandTech got nearly 7 hours of battery life out of the 11" MacBook Air, which is impressive from such a small package!
  8. ccsicecoke macrumors regular

    Aug 19, 2010

    The result indicates only a significantly faster CPU is able to help getting more battery life, which is why the MBP lasts longer than MBA in the end.

    See the difference between 1.86GHz from 13'' and 1.4GHz from 11'' in the last chart. There is not much difference since 1.86GHz is not that fast for normal CPU intensive task.

    So what I understand is the best choice for normal intensive use would be either getting a 1.4GHz or much faster 2.4GHz+.
  9. plesset macrumors member

    Mar 23, 2004
    I have the 1.6 and I have been getting 5 plus hours of usage on mine with the display set at around 60%. I think one thing to remember is that the only way the slight increase in power would be an issue is if you were doing cpu intensive tasks for the duration of the battery charge. For normal usage like web browsing, emailing, word processing you are not taxing the cpu like you would if you were encoding video's or other high cpu tasks. The battery life should be about the same for 90% of the people using this laptop.

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