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11" - i5 vs i7 battery life and heat difference

Discussion in 'MacBook Air' started by entatlrg, Jul 24, 2011.

  1. entatlrg, Jul 24, 2011
    Last edited: Jul 25, 2011

    macrumors demi-god


    After searching and reading there's not a lot of feedback comparing the 11's two processors in real life use.

    As BTO's get delivered that will change.

    Questions I think many of us prospective buyers have:

    1. Does the i5 processor have longer battery life than the i7? How much longer?

    2. Is there a noticeable difference in heat? If so, do the fans run louder and more often?
  2. mac jones, Jul 24, 2011
    Last edited: Jul 24, 2011

    macrumors 68040

    I don't want to cause trouble (unlike some others :D )

    But i'm returning the 11" i7.

    Heat is a major issue. It's really bad. I also have the 1.6ghz core duo version ULV, and THAT runs cool as a jewel .

    I'm going to try the 1.6GHZ version, even though I have doubts. I'm pretty sure that is a Easy bake oven also, but I may keep that, not sure.

    As if you couldn't predict this.

    Oy vey :rolleyes:
  3. macrumors 6502a


    So many people in this forum are asking the i5 vs i7 thing. anandtech.com is likely writing an Air review (the usually reviews Apple products) which almost always includes extensive battery tests.

    I can't say if they will explicity address your question but are one of the best at detailed reviews. Why don't you wait a week and see?

    Here are two sneak peek charts tweeted Friday:

  4. macrumors demi-god


    Thank you, from your posts I respect your judgement, now I can stop searching and reading.

    I love my 2011 11", but the added power will be nice on occasion, for sure the i5 can handle my work, no need for extra heat.
  5. macrumors 6502


    And from your posts I respect your judgement and opinion. I know you've been on a few threads asking about heat issues and battery life so I'll assume you're maybe a bit further ahead than I am in having assessed the current situation. So, are you returning the 11" i7? I have that model on the way and am concerned about heat issues as well. Battery life doesn't really concern me. I definitely don't need the i7, the i5 would be plenty for me; I got the i7 because I want to have this machine for a few years and wanted to "future proof" as much as possible.

    I've decided to wait until it gets here, use if for at least a week and then decide.

    Where are you at in the decision making process?

  6. macrumors demi-god


    I think we've decided, lol. But from what I've read so far I'll be ordering 13" i7's and 11" i5's for my company. All 4gb 256's of course!
  7. macrumors 65816

    It seems like the i7 do run cooler in the 13". Probably due to more physical space.
  8. macrumors G4

    I don't think Anand has a Core i7 model, though. The i7s have been available in the stores, and the first CTO orders should be arriving tomorrow, so more and more of us will have the i7. I have it and set it up, but don't have an i5 to compare it with. Perhaps someone with both (e.g. Apple Expert) could run a Handbrake or iTunes encoding test to get some idea of the performance difference and the CPU temperature.
  9. macrumors 6502


    @dugbug thanks for posting that info. As usual, I look forward to the Anandtech reviews. Add me to the crowd interested in the 11" i5 vs i7 comparison. I'm satisfied that the i5 is all that I need but I'd consider the i7 if it didn't reduce battery life or have significantly more heat.
  10. macrumors 65816

    Speed wise there is a difference a few seconds. I installed iWork on both machines. The install file was located on each desktop. The i7 clearly won. It beat the i5 by a solid 4-5 seconds. I also installed autocad which runs smooth on the i7. Again both installs from desktop. i7 must of installed it about 15 seconds. It was that fast. The i5 was several seconds behind.

    Now your probably wondering heat? The i7 must be running hotter? Wrong! Actually when I glanced the i5 was higher by a few degrees. That shocked me. But neither fan went above 2200 during install. I don't know if the i5 need to try harder to keep up, which would mean more heat?

    The i5 is good, but i7 is better. For those in the USA the upgrade might be worth it. The price for the i5 at apple store it was 1550. The i7 was 1630. $80 more felt worth it to me to shave off some seconds. But to each is own.
  11. macrumors G4

    So are you keeping the i7? At one point you were going to return it to get the i5 because the heat was bothering you and you didn't notice much difference. But if now you are saying the heat's about the same and you do notice the difference, then that takes care of both objections.
  12. macrumors 65816

    The problem was the i7 had to index itself since I had a lot of data on there. That was why I had lots of heat and fan noise. Since then I'm pretty much at 50c with 2k rpm. Will I keep it. Yah I think so. But I'm tempted to get an i5 from amazon since I have a $300 gift card there. Just came across that yesterday. My out of pocket cost on an i5 would be 1300 vs the 1765 I paid for the i7. Big difference in out of pocket cost.
  13. macrumors 65816


    So Im debating about which 11" to get too. Got two questions...

    First, is the effect on battery noticeable between the i5 and i7? Doesn't seem like anyone has answered this yet unless I missed it.

    Secondly, what made me wonder was this post I read on another forum. I'm curious how much truth is in it so I was hoping someone who knows far more than me could clear it up.

    Are you sure about the Core i7 option draining more power? Both Core i5 and Core i7 ave a 17W TDP, and my understanding was that Intel "bins" i's processors so that ones which can operate faster within the thermal envelope have their multipliers locked to higher speeds, whilst ones which cannot sustain this and run hotter or are less stable have their multipliers locked lower. Of course this may be a historical situation that, with today's manufacturing processes, is no longer true...

    Regardless, my understanding of SpeedStep & Turbo Boost is that the processor will always run as fast as possible without exceeding it's rated TDP - so you'd expect either Core i5 or Core i7 to run at just shy of 17W power dissipation under load, and for both models to clock-down to much lower than their rated speed when idle to hit the same minimal power usage as each other. In between, the Core i7 may use more power per unit time, but it will also complete faster - with the trade-off likely in its favour.
    Oh, and Ill be using it for the basic stuff as well as some aperture (raw images) as well as some web-design stuff (Coda/Photoshop, etc).

  14. macrumors demi-god


    i5 vs i7 11" heat comparison

    Agreed, still not a definite answer on battery and heat comparison.

    Takes a special person to have access to both an 11" i5 and i7 ...

    Maybe an Apple employee or vendor or some lucky bugger who bought both to try them out :)
  15. macrumors 6502a

    Well... if we get someone with an i7... I have an i5 (and I'm sure many others have an i5)...

    So why don't we just get a couple willing people for each end (2x i5 11-inch users, and 2x i7 11-inch users), and put together a 60 minute test. Each person should be doing identical things with identical brightness, and identical colour/contrast calibrations... identical everything down to the programs, screen, wireless distance, bluetooth on/off, etc, etc.

    Here would be a good test (with caffeine running):

    To determine if the processor is any different in battery life, the screen should be turned down to 0% brightness. Bluetooth, Wi-Fi, and anything else that could skew the results should be turned off. Load up a high-def video, a couple of background programs, and something else... so that the processor is spiking up and down (not full blast but back and forth as if it were moderate to intense usage), and do this for 60 minutes. Record the % lost in the 60 minutes.

    Then for another 60 minute test, do low-end stuff. Just run a word processor program in the background, with iCal up, and a couple of other very simple programs that would be possibly used when doing word processing. Make the processor run between 0% and 10%. Record the % lost.

    Then for another 60 minute test, do a full-blast test. Keep track of the maximum heat. Run a high-def video, and run a game of some sort (leave it running and on the game); some sort of free game... I don't know. Something somewhat demanding. Keep the processor at 80-100% always.

    Between these three tests we'd have our answer:
    - Max temperature between the two
    - Battery life between the two in medium usage, low-end usage, and high usage

    This would give us probably the best idea of which processor is better for battery life since it would cut out the screen altogether (turning off the backlight really would cut out its power consumption and get us a better look at just the processors going at it).
  16. macrumors demi-god


    How's heat and noise been with your 11" i5's been so far?
  17. macrumors 65816

    How has the heat and noise been in your 13" i7?
  18. macrumors demi-god


    Well ... not bad ... now that I've had it a few days the palm rests and bottom is warmer than my 2010 13" MBA. More noticeable on the lap for sure.

    When I run Microsoft Word / Publisher via Fusion the fans can be heard, the bottom and palm rests warm up pretty good.

    I'm wondering if the 13" i5 would be cooler doing these tasks, would fans kick in later?

    Makes me glad the 11" we ordered is an i5....
  19. macrumors 65816

    I'm in the same boat. I noticed it does stay cool when using the web. Today I was using my MBA and my wife was on hers. I glanced to see her temp. It was 41C while she typed a page using Word and had Safari running. I can't even get 41C on boot up. Makes me wondering if I should give up the 8-10% speed increase for the i5 and run cooler.
  20. macrumors demi-god


    My i7 was a BTO .... I may make a two hour drive to the Apple Store tomorrow and pick up an i5 myself, lol.

    I haven't seen or read any complaints on the i5 in the 11 or 13"?

    If your wife's noticeably cooler on the bottom or palm rest during normal use?

    Saving a few seconds here or there isn't important me, cool and quiet is more important for sure.
  21. macrumors 65816

    I'm thinking the same way. My apple stores are about 20 minute drive. The i5 seems to be the safe bet in terms of it being cooler. Well the more I look at there temps, the more I get antsy. She's always in the 40's. I may tap 49C, but average is 50-60. Don't get me wrong I love the i7, but the temps are driving me to the i5. As for it being cooler, I can say yes it seems to be. Feels like it's not even on at times. I know when I lift up my i7 it's warm on the bottom. Not horrible, but noticeable. I have another week to decide, but something tells me that since I keep going back and forth on the heat, I should be looking to the i5. I'm not a heavy user on video, so I don't think I will miss the i7. I use photoshop and aperture, but it doesn't appear that will have any effect. Only the initial install will be a second or two slower. I can live with that. What will bother me daily is the temps getting up there. :(
  22. macrumors demi-god


    I feel the same way. Will try and pick up and i5/4/256 tomorrow, hope they have them in stock.

    My 13" C2D powered my 27 ACD fine, I'm sure the i5 will so huge improvement in performance, video, Fusion etc.
  23. macrumors 65816

    Will you be returning the other one, or doing compare test?
  24. NFS
    macrumors newbie

    i5 is perfect

    Thanks to early feedback here I cancelled my CTO i7 and now have an i5 which is cool literally and figuratively plus battery life is excellent. Awesome machine.
  25. macrumors 6502

    Anyone here who knows if the 13" i7 has the same heat problems?

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