Battery Life

Brian did some excellent sleuthing and came across battery capacities for both the iPhone 5s and 5c in Apple’s FCC disclosures. The iPhone 5 had a 3.8V 5.45Wh battery, while the 5s boosts total capacity to 5.96Wh (an increase of 9.35%). The move to a 28nm process doesn’t come with all of the benefits of a full node shrink, and it’s likely not enough to completely offset the higher potential power draw of a much beefier SoC. Apple claims the same or better battery life on the 5s compared to the iPhone 5, in practice the answer is a bit more complicated.

Unlike previous designs, we’ve never had a half node shrink for an s-SKU. Both the iPhone 3GS and iPhone 4S stayed on the same process node as their predecessor and drove up performance. In the case of the 3GS, the performance gains outweighed their power cost, while in the case of the iPhone 4S we generally saw a regression.

The iPhone 5s improves power consumption by going to 28nm, but turns that savings into increased performance. The SoC also delivers a wider dynamic range of performance than we’ve ever seen from an Apple device. There’s as much CPU power here as the first 11-inch MacBook Air, and more GPU power than an iPad 4.

To find out the balance of power savings vs. additional performance I turned to our current battery life test suite, which we first introduced with the iPhone 5 review last year.

We'll start with our WiFi battery life test. As always, we regularly load web pages at a fixed interval until the battery dies (all displays are calibrated to 200 nits).

AT Smartphone Bench 2013: Web Browsing Battery Life (WiFi)

The iPhone 5s regresses a bit compared to the 5 in this test (~12% reduction despite the larger battery). We're loading web pages very aggressively here, likely keeping the A7 cores running at their most power hungry state. Even the 5c sees a bit of a regression compared to the 5, which makes me wonder if we're seeing some of the effects of an early iOS 7 release here.

The story on LTE is a bit different. Here we see a slight improvement in battery life compared to the iPhone 5, although the larger battery of the 5s doesn't seem to give it anything other than parity with the 5c:

AT Smartphone Bench 2013: Web Browsing Battery Life (4G LTE)

Our cellular talk time test is almost entirely display and SoC independent, turning it mostly into a battery capacity test:

Cellular Talk Time

You can see the close grouping of the smaller iPhones at the bottom of the chart. There's a definite improvement in call time compared to the iPhone 5. We're finally up above iPhone 4S levels there.

AT Smartphone Bench 2013: GLBenchmark 2.5.1 Battery Life

Our Egypt HD based 3D battery life test gives us the first indication that Rogue, at least running fairly light code, can be more power efficient than the outgoing 5XT. Obviously the G6430 implemented here can run at fairly high performance levels, so I'm fully expecting peak power consumption to be worse but for more normal workloads there's no regression at all - a very good sign.

M7 Motion Coprocessor & Touch ID Camera
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  • Bossrulz - Tuesday, October 22, 2013 - link

    Hi Anand. I am planning to buy my first iphone in the form of 5S.
    Is it worth to buy or to wait for iphone 6 ?
    Is it good to buy in USA or in the country where I live in ?
    Does iphone have internatiobnal warranty ?
    Reply
  • beast from the east - Wednesday, October 30, 2013 - link

    Intel only ever dominiated in sales, not processing power.

    I have installed Apple systems for 25 years, pre-Intel Macs, Apple's computers had twice the performance per clock cycle than the Intel equivalents. From the Motorola chips through to PowerPC.

    That's one of the many reasons why graphics, video and the scientific community used Macs.

    This chip is a beast, we all know it. With the best relationship in the mobile market with Developers that get paid for their work, a fantastic SDK, and Dev's talking about an hour to recompile to 64-bit. I think Apple will be alright.

    Trying to pick holes is just 'Roid-Rage, plain and simple.
    Reply
  • AngryCorgi - Thursday, November 14, 2013 - link

    The math used in this article is incorrect. It is 76.8 GFLOPS per CORE not for the entire GPU. The GPU should be capable of 307.2 GFLOPS. The rest of that chart is wrong as well in most places.

    @650MHZ, per core, G6430 = 166.4 GFLOPS, (*300/650) = 76.8 GFLOPS, (*4) = 307.2 GFLOPS
    Reply
  • ronnieryan - Saturday, January 11, 2014 - link

    @Anand : Sir could you make a review on the history of the iphone's home button? i would really want to know how tough the iPhone 5s home button. I was an android user and wanted to try something new. New in a sense of a 64 bit processor. But i want to know how strong is the 5s home button. Please do make a review of the home button, i would really want to know. email me for the link if its ok...Thanks :D Reply
  • casualphoenix - Wednesday, January 22, 2014 - link

    Hi Anand,

    Hope you're doing well today. My name is Nate Humphries and I'm the Tech/Science editor at CultureMass.com.

    I've been reading through your iPhone 5S and iPad Air articles in preparation for an article about the A7 chip, and it's been an extremely informative read. I wanted to ask if I could use your benchmark charts in my article if I provide proper citation back to your article. I think they would be very helpful for our readers.

    Let me know how that sounds, and I look forward to hearing back from you.

    Thanks,

    Nate Humphries
    Tech/Science Editor | CultureMass
    nate.humphries@culturemass.com
    Reply
  • besweeet - Sunday, March 30, 2014 - link

    I'm curious as to how this website did their 4G LTE tests... On AT&T, I could probably achieve those numbers. Swap that SIM out for one from T-Mobile, and regardless of signal strength, numbers would dramatically decrease instantly. Reply

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