Battery Life

Battery life remains one of the most important aspects of any mobile device. After all, you can’t really call something mobile if it has to spend most of its time connected to an AC adapter. As a result, battery life testing is one of the most critical aspects of our testing, and it’s something that we spend quite a lot of time discussing internally.

Before diving into our results, I want to start things off talking about testing methodologies. This year we're implementing an overhaul of our web browsing test for battery life, with the Galaxy S7 review being our first chance to deploy it. As far as our long-standing 2013 test goes, at a high level our 2013 test was relatively simple in the sense that it simply loaded a web page, then started a timer to wait a certain period of time before loading the next page. And after nearly 3 years it was time for it to evolve.

Internally, we’ve been discussing reasonable measures to push our web browsing test in new directions to both better represent real-world workloads in addition to ensuring that we’re testing more than just display power. For at least a few devices, it had already become quite evident that our old test was almost purely display-bound to such an extent that even video playback was more power intensive. Other issues that were raised both internally and externally included the fact that the test would not test aspects like CPU governor boosts upon touching the display, and that our test almost entirely ignored things like 2D drawing and display pipeline efficiency.

In recognition of these issues, we’ve spent the past few months working on a new test. In addition to new webpages that are exact copies of many popular websites today to better represent modern, real-world workloads, we’ve added a major scrolling component to this battery life test. The use of scrolling should add an extra element of GPU compositing, in addition to providing a CPU workload that is not purely race to sleep from a UI perspective. Unfortunately, while it would be quite interesting to also test the power impact of touch-based CPU boost, due to issues with reproducing such a test reliably we’ve elected to avoid doing such things.

However, we don’t take these changes lightly. While we’ve validated the workload for several devices, it’s important to emphasize that these results could change in the future as much of this data is preliminary. For the second part of the review I’ll be sure to revisit these results with an expanded dataset. Of course, other than the workload the device setup has been held constant across these tests by equalizing brightness to 200 nits and disabling all background sync to the best of my ability.

Web Browsing Battery Battery Life 2016 (WiFi)

As we can see in the results, the Galaxy S7 and S7 edge both do impressively well. One of the more interesting comparison points here would be against the latest devices like the Huawei Mate 8, which has the Kirin 950.

Our previous test was relatively display-bound so differences in SoC efficiency were often difficult to discern and often masked entirely, but here we can see an enormous spread that is almost entirely due to SoC efficiency. The Huawei Mate 8, which under our previous test seemed to be only slightly above the iPhone 6s Plus, has gained a noticeable lead in this test as the Kirin 950’s CPU efficiency is ahead the competition at this time, although it’s important to keep in mind that CPU efficiency is not the only relevant metric for an SoC.

Interestingly enough, the Galaxy S7’s battery life is almost directly scaling with battery size relative to the Galaxy S6. As we’ll see in the display section, the Galaxy S7’s display is pretty much identical to the Galaxy Note5 and S6, so it looks like the efficiency gains from the Galaxy S6 to the S7 are small if you look at the Snapdragon 820 variant.

Of course, the big question that I’m sure a lot of people are thinking is how the Galaxy S7 and the Snapdragon 820 compare to the iPhone 6s and 6s Plus. Unfortunately, due to timing constraints we weren’t able to get data for the smaller iPhone 6s, but looking at the iPhone 6s Plus relative to the Galaxy S7 edge it’s pretty obvious that there is a power efficiency gap between the two in this test. Despite the enormous difference in battery size - the Galaxy S7 edge has a battery that is 33% larger than the iPhone 6s Plus - the difference in battery life between the iPhone and Galaxy in this test is small, on the order of half an hour or 5-6%. This is balanced against a higher resolution (but AMOLED) display, which means we're looking at SoC efficiency compounded with a difference in display power.

Web Browsing Battery Life (WiFi)

In the interest of providing another data point and some validation of our testing results, I ran both devices through our old web browsing test to see what the results would be for something that should be display-bound. Here, it’s obvious that the Galaxy S7 edge holds a significant lead over the iPhone 6s Plus, although the use of a higher resolution display and an AMOLED display in a high-APL test means that the GS7e is using more power in this test as well. However, when you take these results with our new web browsing test, it becomes evident that a difference in power efficiency is growing as the load on the SoC grows. Similarly, despite the Galaxy S7 being neck and neck with the Huawei Mate 8 in our older test, it loses the lead in our new web browsing test.

Of course, I have caution that all of the data that we’re gathering for the web browsing test is still subject to change, but given the interesting data that it provides it’s important for us to include these results, as we’re reasonably confident that these results are accurate.

Overall though, it’s clear that the Galaxy S7 and S7 edge will have solid battery life, even if device efficiency isn’t quite on par with the very best that we’ve seen so far. An improvement of 15% is going to be noticeable if you upgrade from the Galaxy S6, and anyone upgrading from a phone with an SoC older than the Snapdragon 800/801 generation will see huge improvements here.

Introduction and Design SoC and NAND Performance


View All Comments

  • Belard - Friday, March 11, 2016 - link

    What I find shockingly stupid is the release of these new $600~900 phones, including the latest Moto X, that DO NOT include USB-C connector?! Its been available since last year.

    Apple does things quickly, they come out with technology and release it: such as with the iPhone 5 with its reversible port. How hard is it to do with other companies?

    Motorola (Lenovo) could have done this with their New X to make a bold statement on how they are going to run their business.
  • theduckofdeath - Friday, March 11, 2016 - link

    Probably because Samsung has usage data on what we actually use the USB port for these days. And I guess it's used almost exclusively as a charger. Why force the consumers to buy a bunch of new cables and chargers just because there is a new port out there? I know Apple would do that in a heartbeat, like you said, as they simply see it as a new way to increase earnings on licensing accessories. Reply
  • Azurael - Tuesday, March 15, 2016 - link

    Because USB-C is much easier and quicker to connect? (I certainly find the 5X and 6P much easier to connect in a darkened room - good thing since Google nicked Qi charging.)

    Because USB-C cables and sockets should be (probably too early to say, but by design) far less prone to failure than Micro-B? (Micro-B cables, and not cheap ones - OEM LG/Nokia/Sony/Moto cables, die on me on a weekly basis. About half of the cables I own only work for charging now.)

    I don't know, why don't we still connect our keyboards with the AT connector or PS/2, and our digital video cameras by firewire?

    You don't need new chargers. If you've got dozens of USB-A power supplies, just use an A-C cable.
  • theduckofdeath - Tuesday, March 15, 2016 - link

    I'm not suffering from long connection times when connecting my mobile to the charger. Sure, it would be nice with a more uniform connector, but, if it comes at the expense me having to throw away all old cables, having to bring adapters and generally making life more expensive, I can easily live with a micro USB connector until connectors are entirely a thing of the past.
    Physical connectors for data transfer is really not essential these days. These phones has wifi and LTE connectivity at speeds close enough to any USB connection to make us not bothering transferring anything by wire any more.
  • Belard - Tuesday, March 15, 2016 - link

    Uh, just need to replace the cable or it comes with the phone... not difficult. A flip-able cable is VERY handy, especially in the dark. Unless the end is marked or molded a different shape - you have to LOOK which side is up. Apple changed the cable ONE time, because they wanted a much smaller and better connector.

    So for a top end phone, I want a state of the art connector too. hence, I bought a new Moto G for $220... I lose the stereo speakers, but I saved $200 and have two free color covers I switch out for when I'm in the mood. So maybe I'll stick with the Gs.
  • Bruce Dunn - Friday, March 11, 2016 - link

    For the average cell phone buyer, most of the information in this review goes right over their heads. I hope that part 2 of the review will address in simple language the following:

    Can I read the display in direct sunlight (giving me the number of nits emitted by the display does not tell me this).

    What happens if I drop the phone into a sink full of water.

    What happens if I drop the phone onto a concrete floor.
  • peedroo - Saturday, March 12, 2016 - link

    Maximum screen brightness in high ambient light results
  • s.yu - Thursday, March 17, 2016 - link

    Anandtech is not for the "average cell phone buyer". It's for people who *really want to know*. If there were more of us there would be less rip-off products on the market and everything would be easier, more money would be devoted to R&D instead of marketing and more will be achieved. Reply
  • peedroo - Saturday, March 12, 2016 - link

    Loved the review till now

    But here

    ...they have tottaly diferent results about screen brightness levels when we compair it to the S6. It's better
  • karthik.hegde - Sunday, March 13, 2016 - link

    I think what article needs to highlight more is that the Kirin 950 handily beats SD820 is most of the tests. ARM Cortex-A72 is a great core, released quite sometime ago still doing pretty well. I am sure ARM has new CPUs in the pipeline which will be released soon.

    I wonder if it makes sense for Qualcomm from business perspective to continue designing their own cores, while ARM already offers stock cores with great performance.

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