Previous 1 2 Next 22 Replies Latest reply: Jun 24, 2012 2:55 AM by Shant1998 Branched to a new discussion.
sk0rp10 Level 1 (20 points)

Dear all,


I'm an Italian engineer and iOS developer, who recently bought the brand new iPhone 4S .

As most of you who have bought such device , I'm experiencing poor battery performances , even after the latest 5.0.1 iOS update from Apple.


Therefore I wanted to try to understand what was the real cause of such bad performances and - moreover - why does it seems that only certain iPhone 4S are affected from such battery inefficiency behaviour.


By looking at the Internet, most of the hints lead to the conclusion that a particular mix of Apps - or even just one App ( you may find many pointing at Facebook or Fousquare Apps as culprits for the bad battery performances) may cause this huge power drain.


The only way to match such apparently contrasting reports from users all over the world with the fact that at least one certain cause shall explain the power drainage exeperiencied by us all was - in my mind - to find a solution in what the Apps could do to make things go wrong.


By using the Apple Instruments tool from Apple Developer suite (shipped with XCode) , I found this interesting thing :


it seems that the very cause of battery drainage is a bug in the video card driver , which could be triggered by applications making use of certain iOS APIs.


I found this by looking at the energy consumption graphs extracted from my iPhone 4S and comparing them with other information taken from the device.


It seems that - even in sleep state - and when nothing should use the GPU, there is recorded video card activity. But the most interesting thing is that it seems the device does not recognizes this activity as a power draining activity, therefore my theory is  that iOS can't trigger power saving algorithms to shut down the video card since it can't detect the fact it is consuming battery power.


I will attach here a screenshot taken from Apple Instruments tool which shows a 17% video card activity while energy usage is recorded as to be zero, and even when the Display Brightness is exactly zero, there's still video card activity ( near 1%) , but still no energy consumption is recorded by the iPhone.


I'm writing all this here hoping that Apple will examinate my theory and - if confirmed - will soon release a fix for this annoying issue.



iPhone 4S, iOS 5.0.1, Battery bug
  • sk0rp10 Level 1 (20 points)
  • zeGenius Level 1 (5 points)

    That's a really good find !! I hope that the Apple engineers look seriously into it


    My 4S was absolutely fine until I started playing Monopoly on it (yup a heavily 3D game! ) ... then it just started draining the battery super fast!


    Any ideas how to stop the issue from occurring:


      - e.g. restore to factory settings + restore contacts, bookmarks, etc from iCloud + install apps one-by-one ?!!?



    Will that work?



  • sk0rp10 Level 1 (20 points)

    Hi Neil,


    since the issue is located at the top of the iOS system, i.e. resources management , any software which triggers the bugged iOS code - or makes it enter the bugged state - causes the "lock" of the sleep mode, which obviously drains lot of battery.


    For instance , one of the Apps that surely triggers a bugged behaviour is Facebook App (personally tested on my 4S) , which does not use any 3D graphics , but - since it uses a quite complex and new UI (the side scrolling menubar) - maybe it makes use also of parts of either bugged or untested iOS APIs.


    Once you detect the iPhone 4S is misbehaving, as a workaround you can :

    1. make sure the app you just launched (which caused the "sleep lock") has been completely shut down (close it also from task manager)
    2. close all other running apps - in order to be sure you didn't misidentified the bug-triggering App
    3. perform a soft-reset of the iPhone (keep pressed home and power button for 5 - 10 seconds until the phone reboots).


    Thank you a lot for your feedback, this will help Apple should they monitor this thread.

  • zeGenius Level 1 (5 points)

    Interesting. I am trying to see if this works


    I have:


       - shut down all apps on my 4S

       - turned off Settings > WiFi

       - turned off Settings > General > Bluetooth

       - turned off Settings > General > Network > Cellular Data

       - turned off Settings > iCloud > All = OFF (except Find My Phone)

       - turned off all apps from notification center (IMHO: it does use a cool 3D "roll-down" graphic for new notifications )



       - soft-rebooted


       - my battery is at 58% and I plan to just leave the 4S untouched (screen off)

       - lets see how it discharges (normally, it goes down 10% / hour when untouched)



    I'll get back to you




  • zeGenius Level 1 (5 points)

    Awesome !!! It's been 3 hours since my last post and my battery is still at 57%


    So: I've only lost a measly 1% in 3h ... Great! My 4S' misbehaviour has stopped !!




    Now going one step further in my test:


        Settings > WiFi > ON (however, I currently have no WiFi at the office !!)

        Settings > General > Network > Cellular Data > ON

        Settings > Notifications > only viber, whatsapp, mail, calendar, messages ON




    BTW, FYI: I also have these other settings:


        Settings > Location Services > ON (only for Find Friends, Weather, Find My Phone)

        Settings > Location Services > System Services > All OFF (ex. Cell N/W Search)

        Settings > General > About > Diag & Usage > Don't send

        Settings > General > Siri > ON (with Raise to speak = OFF)

        Settings > Sounds > Vibrate > OFF (for both silent and ringer)

        Settings > Brightness > 40% (with Auto Adjust = ON)



    Leaving the 4S again in a barely-touched (screen off) state. Shall report on battery drain again in ~3h



  • sk0rp10 Level 1 (20 points)

    Great news Neil!


    Since now it's confirmed, I shall share this post as much as possible in order to give a solution to iPhone 4S users and also a good hint to Apple engeneers on how to solve the problem.


    I encourage you to do the same, and spread the word out !

  • Qingg Level 1 (0 points)

    wow..let me try too..get back to u once i tryed

  • zeGenius Level 1 (5 points)

    3 hours later and I've dropped now to 54% ... that's barely 1% / hour !!!!


    This is quite normal for me: I've been receiving and replying to emails, SMS'es, iMessages, etc in these past 3 hours (admittedly, not as heavily as I normally would've used the 4S!)



    Looks good (so far), guyz !!



    Thanx, sk0rp10 !!



  • alwaystubed Level 1 (70 points)

    Great Find! Please submit this using apples feedback system, as well as your developer bug reporting method. This makes real sense!


    Again, Bravo.

  • sk0rp10 Level 1 (20 points)

    Just reported to apple through their feedback system. I'll also shortly report through developers portal.

    Hope we helped fixing our brand new iPhone 4S !

  • Qingg Level 1 (0 points)

    i got drop 2-3% after around 7hr untouched standby without sim card and followed the method u guys this normal?


    i also found out that..everytime i go to setting..and play around battery will always - 1%.

  • sk0rp10 Level 1 (20 points)

    Hi Qingg,

    the standby consumption you report seems to be ok ( 2% in 7 hrs means 350 hrs standby total time, which would be outstanding for an iPhone 4S ) .


    The 1% drop in active mode you experience could strongly depend on actions you perform (i.e. accessing iCloud setting makes you access the internet, and if you are on 3G you could drain considerable amount of battery depending on how is your signal reception) .


    However the battery bug seems to occur mainly in sleep mode  , where an incorrect release of resources prevents the iPhone to go into idle mode , therefore consumption in active mode (it's when you use the iPhone) should not be directly related to this issue.


    There's only one thing it comes to my mind that could affect battery consumption even in active state and that would be related to this issue  ( but this is not proven , it's only a personal thought) :

    Not releasing resources could bring the iPhone in a state in which it has to perform extra tasks in order to harvest them (i.e. force release of memory) which could increase the CPU load and - therefore - battery consumption.

  • quantumket Level 1 (0 points)

    This is great news. I too was suspecting some sort of running graphics engine to be the culprit in the battery depletion.


    I just updated to the 4S from the 3GS and instantly noticed poor battery life. Right out of a full charge I was loosing 1% every 10 minutes on standby, screen locked.


    I read your post and tried a couple of things. First, I kept my apps running, but turned off all location and notification settings. Surprisingly, that solved nothing. The second thing I tried, which is what you suggested, was to close all apps in the task manager. A 97% charge held for roughly 25 minutes.


    To me, this solves nothing. I, nor would anyone esle, excpect to have to tediously close all their apps whener I lock the phone.


    Any news on a 5.02 update?

  • sk0rp10 Level 1 (20 points)

    Quantumket, you're perfectly right.

    What we discussed here is not a solution,

    rather a temporary workaround to the problem

    which could help some of us while waiting for iOS 5.0.2.

    Also , by uncovering the real cause of the problem, I hope that

    Apple engineers could benefit from such information and speed up the iOS 5.0.2 development .

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