Battery life impact of 1.7 ghz CPU upgrade?

Discussion in 'MacBook Air' started by icing, Jun 20, 2013.

  1. icing macrumors member

    Nov 24, 2009
    Hi y'all,

    Do any of you guys have any info on how severe the battery impact of the 1.7 ghz CPU upgrade in the 13" MacBook Air 2013 is?

    It's only $150, and the performance boost looks like it's worth it. Especially considering that the 1.3 ghz model is in some cases slower than its predecessor.

    MacWorld has postet the following test results:

    Battery test movie:
    1.3 ghz MBA (2013): 8 hours 18 minutes
    1.7 ghz MBA (2013): 8 hours 7 minutes
    1.8 ghz MBA (2012): 5 hours 1 minute

    Practically no sacrifice in battery. Results are, however, lower than what I've seen the 1.3 ghz do in other tests. So I wonder if they had the brightness at a 100%, which evens out the difference between the two.

    It gets worse, however:

    Battery Test Peacekeeper:
    1.3 ghz MBA (2013): 5 hours 45 minutes
    1.7 ghz MBA (2013): 4 hours 35 minutes
    1.8 ghz MBA (2012): 3 hours 32 minutes

    Also, I don't know how much of the gap to the 2012-models is because of the operating system. Nap Gap is supposed to have quite a big impact. Which might mean the upgrade from 2012 to 2013 1.7ghz won't mean a lot more battery life.

    Do you know of any other tests comparing 1.3 ghz i5 and 1.7 ghz i7? I need more epirical evidence to support my decision to upgrade ;)
  2. Booji macrumors 6502a


    Nov 17, 2011
    The Peacekeeper results are pretty dramatic - makes a good argument to stay with the i5 if battery life is important to you.
  3. Diversion macrumors 6502a


    Oct 5, 2007
    Jacksonville, Florida
    There are some members who can elaborate but it seems that under load the i7 really starts to drain at an unreasonably fast rate compared to the i5 version.
  4. icing thread starter macrumors member

    Nov 24, 2009
    That's what I thought. The i7 drains battery faster. But remember that it also gets things done faster. Real world results should not be as dramatic, I think. Who runs with a 100% CPU load until the battery is dead? In most cases you have a CPU intensive task that will take longer to complete on the i5.

    I'm leaning a bit towards the i7.

    PCMag tested the i5 battery life to be 15:33 running a light surf test. I don't need that much. Give me some power rather :D

    Of course it depends on how severe the drain is. Let me know if you come across more tests of the two models.

    By the way, GeekBench scores are 22,3% faster on the i7 on average.
  5. curtoise macrumors 6502a

    Apr 19, 2010
    I have both, the i7 will drain the battery faster, i5 is very very fast for any normal task, save your money.
  6. AHDuke99 macrumors 68020


    Nov 14, 2002
    Charleston, SC
    I thought the dual core i7 wasn't much different than the i5, but it's only true benefit is that it comes in quad core models?
  7. icing thread starter macrumors member

    Nov 24, 2009
    My 2012 i5 MBA feels a bit slow sometimes. And the i5 2013 should be even slower in some cases.

    Maybe it's because I'm running with 4 gigs of RAM.

    But $150 to upgrade to 1.7 i7 is cheap, I think. A big battery hit would be a deal breaker. Not price.
  8. yokied macrumors newbie

    Jun 20, 2013
    Below is the money quote from the Macworld article. Basically from the i5 to the i7 is a 25% drop in battery performance for 20% better CPU performance.

    "In the Peacekeeper tests, the new 13-inch standard configuration MacBook Air lasted the longest at 5 hours and 45 minutes, which was 2.5 hours less than in our movie test. The new 13-inch standard configuration model lasted 41 percent longer than the new 11-inch model and 25 percent longer than the new CTO MacBook Air. It should be pointed out, however, that the CTO Air outscored the new stock 13-inch MacBook Air by about 20 percent in the tasks that Peacekeeper repeatedly runs during its battery test."

    At this level I think I'll take the trade-off for the i7 for a faster machine now and with future OSX updates, but it's obviously personal preference. This is my first laptop ever.
  9. defomicron, Jun 20, 2013
    Last edited: Jun 20, 2013

    defomicron macrumors member


    Jun 13, 2013
    Another quote from that MacWorld article:

    "We also ran the tests on “ultimate” configure-to-order (CTO) MacBook Air models from this year and from last year. There wasn’t too much of a battery life hit on the new CTO model compared to the standard configuration; the standard configuration model lasted just 11 minutes longer than the CTO unit that has a faster processor, more RAM, and twice the hard drive capacity. Comparing this year’s CTO “ultimate” to last year’s, we saw that the new model lasted 65 percent longer."

    The Peacekeeper test is a terrible approximation of real world usage. The i7 has shown to have little to no impact on battery life under real world use.

    The i7 will make your machine noticeably faster and in a year or two from now the difference will be even more pronounces. It's an inexpensive upgrade and you can only do it now. If you are in any way leaning toward the i7, just do it.
  10. kap09 macrumors 6502

    Jun 10, 2009
    So far my i7 has been doing great. Charged it up when it arrive and then unplugged while working on reinstalling software and migrating my files. This took hours and the fan was definitely on several times during the progress. Had the screen up to about 85% or so and still did about 11 hours.

    I'm at 95% now and the battery indicator is showing a little over 14 hours left. Screen is at 50%
  11. Diversion macrumors 6502a


    Oct 5, 2007
    Jacksonville, Florida
    Mine shows 19+ hours at 78% battery, 50% brightness, Wifi on, browsing the forum, typing up docs, etc. - mine's an i5
  12. tuffcalc macrumors newbie

    Dec 6, 2012
    I have a base i5 (wife's) and an "ultimate build" i7 (mine). I've noticed little difference in battery life over the last week.
  13. curtoise macrumors 6502a

    Apr 19, 2010
    Do you have an i7?
  14. defomicron macrumors member


    Jun 13, 2013
  15. mattferg macrumors 6502

    May 27, 2013
    YES, but you have to remember this is a base model 13 vs a fully specced CTO.

    Basically meaning a large part of that 20% performance increase can be explained by the increase in RAM to 8GB and the doubling of the SSD write speed to 700mb from 400mb (roughly). Basically meaning the processor adds maybe 10% performance increase for 25% less battery. Definitely not worth it.
  16. defomicron macrumors member


    Jun 13, 2013
    YES, but you just made up those numbers. Pulled them out of thin air. You have no evidence of any kind whatsoever to back them up.
  17. curtoise macrumors 6502a

    Apr 19, 2010
    That's what I thought, thank you.
  18. mattferg macrumors 6502

    May 27, 2013
    Except that it's obvious the battery drain would be down to a higher clocked CPU, whereas the performance gain is obviously a variety of factors.

    Compared to what you posted:

    "The Peacekeeper test is a terrible approximation of real world usage. The i7 has shown to have little to no impact on battery life under real world use."

    which is COMPLETELY out of thin air and benchmarks have proven to be innacurate...

    I think my comment/opinion is more valid and more accurate.
  19. defomicron macrumors member


    Jun 13, 2013
    Are you seriously basing your argument on benchmarks and then claiming that benchmarks are inaccurate? REALLY?

    Do the tests even measure read/write speeds? I'm sure RAM has an effect but I also doubt it's that significant. 4 GB is plenty for the a system. The significant change in performance is most likely the CPU change. Throwing out a number of 10% is ridiculous. You COMPLETELY pulled it out of thin air.

    As for what I said, I'll say it again: the Peacekeeper test is not an approximation of real world use. No one will ever have their MBA run through an entire charge with the CPU at full speed.

    In the real world use test, the video battery test, the i7 performed just as well as the i5. And that has been confirmed by numerous i7 owners on this board.
  20. Jazwire macrumors 6502a


    Jun 20, 2009
    Do you notice much heat difference between your i7 and your wife's i5 under normal operation?
  21. Doc Shultz macrumors newbie

    Doc Shultz

    Jun 12, 2013
    I have the 1.7 ghz and when I am doing things likes browsing the net, writing documents, watching a flick or two, and listening to some music, I am getting between 9-14 hours depending on the tasks. When I play Guild Wars at Max settings, minus shadows and anti alias off, I get about 3+ hours, but it plays at 30-35fps.

    That's what my real world experiences have been.
  22. lshirase, Jun 20, 2013
    Last edited: Jun 20, 2013

    lshirase macrumors regular

    Jan 7, 2008
    When I compared my i7/8/256GB with my brother's i5/8/256, the battery life difference was negligible. On average, his i5 outlasted my i7 by ~25 minutes. I also saw a 1-3C difference in temperature (during heavy load). If you have the money, go with the i7. The extra power is worth it IMO.

    edit: As i'm typing this on my i7, i notice that at 29% battery i still have 5 hours of juice. 50% brightness, watched a movie, a decent number of youtube videos, itunes, photoshop, etc. I get around 12 to 13 hours of battery life on this machine.

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