Battery Life

With the move from featurephones to smartphones, battery life has been and continues to be a critical issue. While it wasn’t unusual to see a week or more of battery life on a featurephone, some of the earliest smartphones couldn’t even last a day. While tablets seem to have a much easier time achieving high levels of battery life by virtue of massively increased volume, they still face similar issues as they are often used for gaming or other more intensive workloads that a smartphone is unlikely to see nearly as often. In order to test this, we run our tablets through a standard suite of tests of various use cases. In all cases where the display is on, all displays are calibrated to a brightness of 200 nits to draw useful relative comparisons.

Web Browsing Battery Life (WiFi)

In our first test, we see that the iPad Air 2 is about roughly equivalent to the original iPad Air for WiFi web browsing. This is actually a bit surprising as the battery in the iPad Air 2 is approximately 84% of the iPad Air. This would mean that we would expect the iPad Air 2 to get around 8.4 hours of battery life in this test, which represents a 16% gain to efficiency. It’s likely that these improvements to battery life come from the new process node on the A8X, along with the newer WiFi module.

Web Browsing Battery Life (4G LTE)

Along the same lines, the LTE web browsing test tracks quite closely but it seems that there’s a minor decrease in efficiency gains when compared to WiFi. This difference is likely to be explained by the much higher bandwidth available in WiFi when compared to LTE.

While the web browsing tests are effective at ensuring faster SoCs aren’t punished, this inherently tilts battery life towards a more display-bound mode rather than compute-bound. Unfortunately short of a jailbreak it doesn’t seem possible to get an effective Basemark OS II battery test, so we’re mostly limited to a test of GFXBench’s unlimited rundown.

GFXBench 3.0 Battery Life

GFXBench 3.0 Performance Degradation

As one can see, the iPad Air 2 is one of the best performers on this test, considering its frame rate and runtime. While NVIDIA's GK20A GPU in Tegra K1 can get close to the GX6650 for short periods of time, over a long workload it's pretty clear that the GX6650 on 20nm has better sustained performance and significantly superior efficiency as it doesn't throttle until the 200th iteration of the test. It's important to note that the iPad Air 2 is running at a higher native resolution here, so relative to SHIELD Tablet a scaling factor needs to be estimated in order to get an idea for performance at the same resolution. During this test I saw that the skin temperatures never exceeded 45C, so this isn't the result of Apple choosing to run the device hotter than most.

Charge Time

While tablets deliver some great battery life in general, charge time tends to be much slower than that of smartphones as the battery is much larger and charging the device isn't as time critical due to the longer battery life . While we can't quite cover the full range of battery life uses cases, it's important to remember that in cases where the platform is otherwise identical beyond display that battery life scales linearly with overall capacity. In order to test charge time, we measure the time it takes for the battery to reach 100% from a fully-depleted state.

Charge Time

As one can see, the smaller battery seems to have a noticeable impact on charge time, although the difference isn't really all that notable as the difference is only around ten minutes at the end of the day.

GPU and NAND Performance Software: iOS 8
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  • sprockkets - Saturday, November 8, 2014 - link

    "Most Android users have no idea.

    ITunes hasn't been required in years."

    Except every ios device has to contact apple to work initially, and either itunes or itunes on the web does this. It's a stupid requirement that apple will never ever let go of.
  • carloshehe - Sunday, November 9, 2014 - link

    You don't have to connect any apple device to iTunes. At all. Ever. You take it out of the box, you turn it on, it asks you a few simple questions and you're on the homescreen.

    What you're talking about is recovery mode. That's the only time I've seen that.
  • NEDM64 - Sunday, November 9, 2014 - link

    Google Play Services is what?

    Google's version of "iTunes on the web"...

    Really? That "iTunes on the interwebs" is the most retarded thing I haver have read here... But two pages from this, and anyone can see the real problem of this user...

    And "iTunes on the interwebs" is welcome, makes a stolen iPhone or iPad worthless, wich if cool, unless you plan to stole one.
  • akdj - Monday, November 10, 2014 - link

    As does Samsung (& Google/AT&T/Verizon/Sprint/Carrier)
    As does HTC (& Google/AT&T/Verizon/Sprint/Carrier)
    As does LG (& Google/AT&T/Verizon/Sprint/Carrier)
    As does {insert OEM here} (& Google/AT&T/Verizon/Sprint/Carrier)
    ....and this DOES include the 'Nexus' lineup. While 'stock Android', it's built by and distributed the largest 'data miners' AND exploiters on the Internet, today. Google. Period
    At least with Apple, sure, you definitely 'register' with them ONCE ...From then on, your communication with them is limited by your choices in settings. If title doing nothing wrong, I don't see a reason to help with 'traffic' or a developer improve his app, etc
    If I'm doing something wrong, I suppose I would shit those options off. No need to 'phone home' as EVERY Android device does, including my Note3 I enjoy so much
    At least Apple's a one shot, you choose deal
    In the world of Android, it's a gamble unless you're using Nexus. Then you're 'only' sharing with Google. Everyone else you're dealing with the OEM and the carrier's bloat ...and constant background, unavoidable and incessantly running 'processes'
    Anyway, yeah...TL/DR
    What did you mean with your quotes?
    A) you don't need iTunes EVEN in the beginning to activate your phone. Use a gmail account as your iPhone check in acct
    B)‘Most Android users have no idea'
    This I disagree with. If argue most ARE aware of this lack of necessity for some time now. Bad thing is you don't ..yet you quoted something you clearly don't understsnd, didn't realize and failed to respond with a 'back up' to your complaint(s)
    It's neither a 'stupid requirement'
    And Apple only held on to it so it could sync your phone in an expeditious manner! Wireless, broadbamd and 'clouds' have t been here forever.
    That said, iTunes eats KIES alive. It's definitely the first thing replaced on my Note updates. Music and media management. Unfortunately, one still has to deal with it for OTA updates
    I'll take the iOS 'update' approach (to both apps and full on OS upgrades all day in comparison)
    As akways, ymmv
  • robinthakur - Monday, November 10, 2014 - link

    Except every Google device has to contact Google to work initially, and all the time thereafter, feeding them yopur usage metrics to make them money. It's a stupid requirement that Google will never ever let go of.

    There we go, fixed that right up.
  • extide - Monday, November 10, 2014 - link

    Actually you can use an Android device without ever even having a google account. Obviously things like gmail and the play store wont work, but the option is there if you really wanted.
  • akdj - Thursday, November 27, 2014 - link

    No different than Android devices using your Gmail information for 'initial contact'
    There's NO NEED to use iTunes. iTunes on the web. iTunes on your iPhone! There's hundreds of programs to play your media from
    And the 'need' to contact Apple, use iTunes or any of the other BS you've been told a couple dozen times now hasn't been the case since 5.0, right?
    This is 8.1. So over three years have passed
  • carloshehe - Sunday, November 9, 2014 - link

    In all fairness you do need iTunes still. How will you put all your music in an iPad? Maybe you'll say there are other programs out there you can use, but the fact is you still have to sync it and use some sort of program to put your music.

    You have 3,000 songs in your computer. You get an iPad. How are you going to put all that music in your iPad?

    With Android you can just plug it in and drag and drop your music like the tablet is an external drive.

    That being said, Android sucks because it has no tablet apps.

    Android tablets are for the very basics. Documents, email, videos. But for anything else, you need an iPad.
  • akdj - Monday, November 10, 2014 - link

    Sync via home sharing (playlists)
    Dropbox GDrive OneDrive
    iTunes match up to 25,000 songs with ya, everywhere you go ...just $20/year
    There's Sooo many options to list, no need to 'sync' your media any longer with your computer physically connected. If you're on you're gime network, feel free to send me a line and I'll walk you through.
    All3,00 songs;)
  • akdj - Thursday, November 27, 2014 - link

    I'm blown away by the ignorance here
    Wow. You'd think half these comments are being made by someone who's never used an iPhone, an iPad. iOS period. Much less a Mac or iTunes ITSELF, no, you do NOT need to 'plug in' to get yiur music. If you've got a hundred thousand, yes. Because a TB or two won't fit. Then, it's as easy as plug in to .mac or PC, sync managment and check the boxes to sync (playlists, artists, all...whatever).
    A signficantly better media managment system in aggregate than ANY other in the world
    I use Plex. I use Traktor, I edit audio in Audition, video in premier...but like anything else, organization is key. And iTunes has it nailed.
    Kies. Sucks ...,and it's the other AIO organizer forced upon you by the biggest (by a HUGE margin) OEM making Android phones. Samsung.
    As well, since you know so little about iOS, I assume the same is true with iTunes. It's come a VERY long way since you had to 'connect' your iPhone

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