Why doesn't Macbook Pro have Air-like standby battery life?

Discussion in 'MacBook Pro' started by Elusivelattice, Oct 26, 2011.

  1. Elusivelattice macrumors newbie

    Joined:
    Oct 26, 2011
    #1
    Here's a question I never see discussed or brought up...but why exactly is the Air capable of 30 days standby battery life but the Macbook Pro isn't? Is this another one of Apple's arbritrary differentiators for the sake of setting products apart from one another or is there a proper explanation for it? Does the more beefy processor somehow influence standby power consumption?

    I find that I realistically use my laptop intermittently throughout the day, so it's being put to sleep quite often. With the Pro I just bought (late 2011) that results in a lot of wasted battery life with the thing not even being used. It's one of the biggest factors I was considering prior to the purchase, and still can't decide whether it's substantial enough of a difference for me to care.

    I have a 120 GB SSD installed in the macbook pro, so as far as the hdd space goes, I have what is essentially equivalent to an Air anyways. Is it justified to keep the Pro for that extra processor speed if I'm not using the computer for anything crazy?

    My reasoning was:
    1. Upgradability, including possibly going the Opti-bay route http://www.mcetech.com/optibay/ (which I realize will degrade battery life even further)

    2. IF i were to ever need the processing power, it would be nice to have it

    Question is, are those factors worth sacrificing the Air's standby battery life and size?

    What are your thoughts?
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
    Location:
    located
    #2
    Just out of curiosity, why do you need 30 days standby time?

    The MBA's standby time obviously comes from its flash storage, as the contents of the RAM can be written to it faster than an HDD, thus it goes into hibernation.

    You could use SmartSleep (or Terminal) to enable hibernation on your MBP and thus disable SLEEP.

    Btw, it is okay to use the MBP, even while asleep, with a power adapter.

    ______________________________________________________
    This should answer most, if not all, of your battery questions:
    Apple Notebook Battery FAQ by GGJstudios
    ______________________________________________________
     
  3. Elusivelattice thread starter macrumors newbie

    Joined:
    Oct 26, 2011
    #3
    Hahaha, yes I know it's okay to plug it in, I'm speaking for those times where an outlet isn't readily available. I don't need 30 days of standby battery per se, however considering it's capable of 30 days of standby, I would assume that means if I had it in standby and unplugged for, lets say 3 hours, a Pro would lose probably around 3% of its battery while the air would have lost substantially less. Adding up all the times I put the computer to sleep within a typical 12 hour day, it might be a factor.

    Do you have any more details on enabling hibernation? Perhaps links or something? Seems like a viable option for those who have SSD's installed in their Pro's like me.
     
  4. simsaladimbamba

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    Nov 28, 2010
    Location:
    located
    #4
    "mac os x enabling hibernation", "smartsleep"
     
  5. Elusivelattice thread starter macrumors newbie

    Joined:
    Oct 26, 2011
    #5
    Does anyone know the exact mechanism by which the Macbook Air sleeps/hibernates? It's instantly on when opening the screen, so it doesn't seem to be hibernating. What exactly is it doing to achieve the 30 days standby? I'm not necessarily looking for a way to make my macbook pro do the same, tweaking it to hibernate instead of sleep is fine, but I'm really just curious to know what technique apple is using to achieve the standby battery life the Air gets.
     
  6. heisenberg123 macrumors 603

    heisenberg123

    Joined:
    Oct 31, 2010
    Location:
    Hamilton, Ontario
    #6
    do MBA's come with SSD hard drives? maybe thats the difference, it hibernating but the SSD is so fast to wake you dont think its hibernating at all? just a guess
     
  7. maril1111 macrumors 68000

    maril1111

    Joined:
    Mar 14, 2010
    Location:
    Denmark
    #7
    Check this thread for how it does it:

    http://forums.macrumors.com/showthread.php?t=1050278
     
  8. Elusivelattice thread starter macrumors newbie

    Joined:
    Oct 26, 2011
    #8
    Thanks for pointing me in the right direction!

    To summarize in case someone stumbles upon this post and wants a quick answer:

    Since the macbook air is designed to be used with an SSD, there is an option enabled for "deepsleepdelay" where it basically works like this: When you close the lid on your air, the computer enters regular sleep and the session is stored to ram (some power is used to power the ram). After about 70 minutes, the content written to ram is stored to the disk and the ram is turned off, thus battery usage drops to pretty much zero.

    There is no option for tweaking deepsleep settings in terminal for the MBP as it needs to be supported by the hardware. In this case, MBA is the hardware supported and not MBP.

    However, one could force the computer to "deep sleep" or hibernate instead of sleeping altogether in order to save battery, but this would probably not be advisable for those with HDDs OR for those with SSDs. Why?

    HDD users: the time it'll take to restore your session will be substantially longer than what you're used to with regular sleep.

    SSD users: the content of your session is stored to disk every time you close your lid, which runs down your SSDs lifespan. However, technically with "safe sleep" that Apple has enabled by default, your session is saved to disk every time you close the lid of the computer anyways. In otherwords, the session is stored to both ram and disk; stored to ram for quicker resume and stored to disk in case of power loss. This might be the safer option, but in my opinion, you get "the best of NEITHER worlds", especially for those with SSDs.

    What apple should have done was keep the deep sleep delay arguments available for any hardware configuration, just in case someone buys a MBP and throws an SSD in it (like I and many others have). Seems silly to restrict it to just the air.

    I'm leaning toward disabling safe sleep via this command: "sudo pmset -a hibernatemode 0" and either using manual terminal tweaks, a tool to enable hibernation when I want to hibernate, or just shut down the computer if I feel like I won't be using it for a long period of time. Definitely not as elegant, but seems like the best option since Apple seems to like imposing arbitrary restrictions on their hardware lines :mad:
     
  9. Elusivelattice thread starter macrumors newbie

    Joined:
    Oct 26, 2011
    #9
    upon further investigation, there is actually a way to completely emulate the Macbook Air's standby behavior.

    This applies for those using Mac os x 10.6.8 or newer. For those using older versions, substitute "standbydelay" and "standby" with "deepsleepdelay" and "deepsleep" respectively.

    Here are the steps:

    1. Open Terminal
    2. Type the following: sudo pmset -a standby 1

    and that's it! if you type in "sudo pmset -g" it'll show you what your current power settings are set to. there should be a line that says "standbydelay" and then a number (likely 4200). This is the number of seconds it will wait before hibernating. You can adjust this number by performing a similar step to step 2 above. For example, if you want it to wait 2 hours (7200 seconds) before hibernating, you would type "sudo pmset -a standbydelay 7200"

    Thats it! now your macbook pro should theoretically behave like the air, that is, it will sleep when closing the lid and only enter hibernation after however many seconds is set under "standbydelay". Ideal for a nice balance between SSD maintenance and battery life when sleeping!
     
  10. Rhyalus macrumors 6502

    Rhyalus

    Joined:
    Mar 4, 2011
    #10
    Has anyone confirmed this?

    I have a 2011 MBP and did a "man pmset |more".

    Note this section on "standby":

    STANDBY ARGUMENTS
    standby causes kernel power management to automatically hibernate a
    machine after it has slept for a specified time period. This saves power
    while asleep. This setting defaults to ON for supported hardware. The
    setting standby will be visible in pmset -g if the feature is supported
    on this machine.

    standby only works if hibernation is turned on to hibernatemode 3 or 25.

    standbydelay specifies the delay, in seconds, before writing the hiberna-
    tion image to disk and powering off memory for standby.

    But...here is my pmset -g, which does not show anything about standby. I am using 10.6.8.


    Active Profiles:
    Battery Power -1
    AC Power -1*
    Currently in use:
    hibernatemode 3
    halfdim 1
    lidwake 1
    acwake 0
    womp 0
    sleep 0
    disksleep 10
    sms 1
    hibernatefile /var/vm/sleepimage
    ttyskeepawake 1
    displaysleep 15


    Thanks,
    R
     
  11. Elusivelattice thread starter macrumors newbie

    Joined:
    Oct 26, 2011
    #11
    Strange, your pmset -g results look very different from mine. I have a late 2011 macbook pro, and mine looks like:

    Active Profiles:
    Battery Power -1*
    AC Power -1
    Currently in use:
    standbydelay 4200
    standby 1
    halfdim 1
    sms 1
    panicrestart 157680000
    hibernatefile /var/vm/sleepimage
    disksleep 10
    sleep 10
    hibernatemode 3
    ttyskeepawake 1
    displaysleep 2
    acwake 0
    lidwake 1

    I'm running 10.7.2
     
  12. Rhyalus macrumors 6502

    Rhyalus

    Joined:
    Mar 4, 2011
    #12
    Thanks for posting that....

    Anyone else with 10.6.8 that can post their pmset -g?

    I wonder if you need Lion to get the benefit of this standby feature.

    R
     
  13. Rhyalus macrumors 6502

    Rhyalus

    Joined:
    Mar 4, 2011
    #13
    Hello - can someone with 10.6.8 open up terminal and tell us what their pmset -g looks like?

    Thanks,
    R
     
  14. cps macrumors newbie

    Joined:
    Apr 22, 2011
    #14
    Active Profiles:
    Battery Power -1
    AC Power -1*
    Currently in use:
    womp 1
    halfdim 1
    sms 1
    hibernatefile /var/vm/sleepimage
    gpuswitch 2
    disksleep 0
    sleep 10
    hibernatemode 3
    ttyskeepawake 1
    displaysleep 10
    acwake 0
    lidwake 1
     
  15. vitzr macrumors 68030

    vitzr

    Joined:
    Jul 28, 2011
    Location:
    California
    #15
    While I both understand & can appreciate what you are trying to accomplish. I have not encountered a lack of battery life with my 15" 2011 SSD equipped MBP. I have many days where it's used on & off frequently throughout the day. I use sleep mode which works very well. Alternately when I am using my 17" 2011 SSD equipped MBP, I typically shut down the 15". The reason being, boot times are so fast I have no adversity to turning it off.
     
  16. dusk007 macrumors 68040

    dusk007

    Joined:
    Dec 5, 2009
    #16
    It also strikes me as quite useless.
    A 12h day you let it sleep
    it sleeps for 70 min
    it shuts off
    You wake it after 2 hours
    you work
    you let it sleep again
    ...

    You really wouldn't save a whole lot. Considering sleep power draw is around 0.6W on a MBP. That saved you in one such cycle maybe 1% battery life 1h standby 2h shutdown. On a whole day (that can suck the battery dry) say 4h working, 8h sleep. You save 4% battery life. That really doesn't make any difference and in any other case you would recharge that evening anyway.

    The only thing it gets you over real standby is that if you close it and need it again right away because you forgot something it is back much faster.
    Still I'd prefer do disable hibernation and it enters sleep in seconds and is back just about immediately. Faster sleep/wake cycles also save battery life.


    Seriously that feature is something for people who put their MBA into sleep and put it on the living room table and forget it there, or people who take it on a trip (holiday/business) in sleep mode and only need it once or twice.
    It is just about useless for somebody who actually uses a notebook very often and/or is smart enough to hibernate it if he means not to use it for an extended period of time.

    @vitzr Just using hibernation should still beat a shutdown/boot cycle. The unfortunate thing with Apple is that unlike Windows there is no default switch for one or the other. A script would do though.
     
  17. Zeov macrumors 6502a

    Zeov

    Joined:
    Apr 1, 2011
    Location:
    Odense
  18. Rhyalus macrumors 6502

    Rhyalus

    Joined:
    Mar 4, 2011
    #18
    Thanks to CPS and others who have replied to this string.

    First conclusion is that Snow Leopard does not have this feature. I dread moving to Lion - my current OS works perfectly - never a hiccup.

    To the other folks who commented on this not being necessary, you are right that it is not the highest priority. It is a nice feature when you travel a lot and may not have access to power for a long time or at night when the laptop can slip into deep sleep so that the battery is not drained at 1% / hour (I agree with your calculation, Dusk - this is what I see here).

    I may create a batch file or something to manually switch pmset in and out of mode 25 before closing the lid.

    Most of the time, the quick wake is worth the 1% / hour, but it is a nice feature to choose deep sleep instead.

    R
     

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