Inside iOS 9: Under-the-Hood Improvements for Battery Life, Security, and More

Discussion in 'iOS Blog Discussion' started by MacRumors, Sep 16, 2015.

  1. MacRumors macrumors bot


    Apr 12, 2001

    In iOS 9, some of the best features are the ones that aren't readily visible. iOS 9 has several under-the-hood updates that boost battery life, improve security, and cut down on the amount of storage space iOS updates and apps use on iPhones and iPads.

    Even disregarding all of the consumer facing features, these quiet improvements make the upgrade to iOS 9 from iOS 8 or iOS 7 well worth it on all supported devices: the iPhone 4s and up, the iPad 2 and up, and all iPad mini models.

    Battery Life

    With operating system optimizations, Apple is able to eke out an additional hour of battery life on iPhones under normal usage conditions. One of these improvements, for example, pertains to the iPhone's ambient light and proximity sensor. When the iPhone is placed facedown, it now detects that the screen isn't visible, so an incoming notification does not light up the screen.


    There's also a new Low Power Mode on the iPhone that can add another three hours of battery life by cutting down on battery-draining features. Low Power Mode turns off automatic Mail fetch, disables background app refresh, disables motion effects, and disables animated wallpapers.

    Low Power mode also throttles the performance of the iPhone so it drains less power. Benchmark testing suggests Low Power mode reduces an iPhone's performance by about 40 percent to cut down on power usage.


    iOS 9 prompts users to create 6-digit passcodes instead of 4-digit passcodes for additional security. It's still possible to create a 4-digit passcode, but Apple recommends a 6-digit code because it adds one million possible combinations instead of 10,000, making a passcode harder to crack. Two-factor authentication support is also enhanced in iOS 9.


    Installation Size

    With iOS 9, Apple's cut way down on the installation size, so far less free space is required to download the new update. While iOS required 4.58 GB of space to install, iOS 9 requires only 1.3 GB of space to install, making it more accessible to users who have 16 GB iOS devices.


    For devices that still don't have enough space to install the iOS 9 update, Apple has a new auto app delete/reinstall feature. When attempting to install iOS 9 on a device with insufficient space, there's a popup that offers to temporarily delete some apps in order to make room for the update. Apps that are deleted are then reinstalled and replaced after the operating system update is completed.

    App Thinning

    Apps from third-party developers also require less installation space thanks to a feature called App Thinning. With App Thinning, apps can be optimized for specific devices, allowing them to take up less space on iOS devices.

    An app for the iPhone doesn't need all of the iPad assets, so those won't be downloaded. That means faster installs, faster launch times, and more storage space left for other apps and content.

    App Thinning also includes on-demand resources like image and sound files, which can be downloaded only when needed. The imagery for later levels in a game, for example, might not be downloaded until it's necessary.


    Apps in iOS 9 take advantage of Metal, making more efficient use of the CPU and GPU for faster scrolling, smoother animations, and better performance. Email, messages, web pages, and PDFs all render faster.

    Article Link: Inside iOS 9: Under-the-Hood Improvements for Battery Life, Security, and More
  2. JCrz macrumors 6502

    Sep 12, 2014
  3. Mr. Donahue macrumors 6502

    Mr. Donahue

    Sep 17, 2014
    I'm still waiting for an update to apple music. So many little bugs. Issues.

    I'm also waiting for the day I can add photos to any photo album even if I uploaded the photo album from my MacBook to iPhone I still want to be able to make changes and add to and delete.
  4. Mackker macrumors member

    May 22, 2015
    iPhone 4S: battery sucks big time (6% lost in almost 5 minutes) and performance without Low power mode enabled is awful!
    Why Apple engineers don't design software on less capable devices first and move on from there?
  5. Zwhaler macrumors 604


    Jun 10, 2006
    Is iOS 9 definitely faster equal or faster on the 4S? It sure wasn't on iOS 8.
    edit: the guy above me who posted as I was writing this answered my question.
  6. Mackker macrumors member

    May 22, 2015
    With Low Power Mode ON is definitely faster than iOS 8!
  7. nagromme macrumors G5


    May 2, 2002
    Because then the software will be less capable, and devices newer than the 4S would go to waste.
  8. devinthomas macrumors regular

    Mar 16, 2013
    When does Two-factor authentication roll out? I'm still getting Two-step verification on El Cap GM & iOS 9 public release.
  9. Maleption macrumors member

    Sep 15, 2013
    About tansfer puchase back to iTunes:

    How A universal app on iPad with app thinning enabled get transferred back to iTunes? And can we install that IPA to a iPhone?
  10. arkmannj macrumors 68000


    Oct 1, 2003
    How's it on the iPhone 5? I was doing the Beta's but a couple weeks ago was fed up with the bugs. (Beta, I didn't blame Apple, but I didn't want the bugs anymore either) Did they get some of the stability and such ironed out?
  11. TMRJIJ macrumors 68040


    Dec 12, 2011
    South Carolina, United States
    It's the first day and it's indexing. You can complain about it tomorrow but right now we hold your review with a grain of salt.
  12. Mackker macrumors member

    May 22, 2015
    I disagree. I'm an iOS Developer and I know what these devices are capable of.
    That's one. Another thing would be that designing software on less performant devices will lead to great performance advantages for more performant ones. Also, who says that designing software for slower devices will impair new or more features for the faster ones? At its core the software must be fast!
  13. cariacou macrumors 6502a


    Jul 21, 2010
    so much effort required from so many developers (Apple, 3rd party) so that Apple can save $5/device by not moving to 64GB base...
  14. cariacou macrumors 6502a


    Jul 21, 2010
    iOs 9 was publicy released today
  15. Mackker macrumors member

    May 22, 2015
    I've been using the iOS 9 GM for a few days. Nothing changed. You can take my review as granted.
    As I said in another comment: with Low Power Mode ON, the OS is definitely faster on iPhone 4S. The only "issue" would be that the function gets automatically disabled when the device is charged after a certain threshold (60% I think).
  16. Mr. Donahue macrumors 6502

    Mr. Donahue

    Sep 17, 2014
    Also I want to be able to fingerprint ID enabled for purchases but I don't want it enabled for lock screen and I don't want a password ever.
  17. 0098386 Suspended


    Jan 18, 2005
    I've been on 9GM for about a week now. I really like it! It's very smooth, and my battery life seems slightly better too. I'd like that emergency battery mode thing to have a control centre shortcut, though.

    Love the new font too. Very readable.
  18. postpc macrumors regular


    Sep 3, 2013
    I've been hard on Apple for the last couple of months, but IOS 9 feels brilliant. No Safari crashes so far, and its snappyness has been taken up or notch, everything feels fast and fluent on my dated Ipad 4. Looks like this could be the long awaited Snow Leopard release.
    Well done Apple, credit where credit is due.
  19. Zwhaler macrumors 604


    Jun 10, 2006
    Is it faster than iOS 7 though?
  20. Parasprite macrumors 68000


    Mar 5, 2013
    This is pretty minor, but for devices with a keyboard, they've also added a helpful popup when you hold cmd that shows what keyboard shortcuts you can use.

    Not a huge feature, but it's definitely a nice touch.
  21. elmateo487 macrumors 6502a

    Jun 12, 2008
    Are you saying app thinning is a bad thing? I shouldn't have to download resources I don't need...
  22. Mackker macrumors member

    May 22, 2015
    If I remember correctly, with iOS 8 Low Power Mode ON, it feels almost exactly like iOS 7 (it's been a while since I last used iOS 7 on this device).
  23. macs4nw macrumors 601


    But... but...but... necessity is still the mother of invention..... these optimizations can only help us down the line.
  24. Glassed Silver macrumors 68020

    Glassed Silver

    Mar 10, 2007
    Kassel, Germany
    I can't wait for this becoming an issue when abroad and without good data allowance. (if any)

    Glassed Silver:mac
  25. Hardingster macrumors newbie

    Jul 10, 2008
    I am not seeing a reduction on the iOS9 installation size. I have a 16 GB iPhone 5. Capacity is showing 12.5 GB after installing iOS9.

    Anyone else seeing this?

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