Platform Power & Battery Life

The new Nexus 7 moves to a slightly smaller battery compared to its predecessor (15Wh vs. 16Wh). The result however is anything but a reduction in battery life. ASUS and Google worked hard to reduce platform power consumption as much as possible. I instrumented both Nexus 7s and measured total platform power, excluding display, to look at the impact of the silicon platform (SoC, PMIC, DRAM, eMMC, WiFi, etc...). The results are beyond impressive:

Idle power is cut in half compared to last year's model. This is by far the most important improvement as most mobile usage models tend to have long periods of idle time. We'll see these power gains reflected in our web browsing test which does have significant periods of simulated reading time between web page loads. The power reduction while running Kraken grows to just over 20%, and even while running Geekbench 3 we see a 16% drop with the new Nexus 7. Only our offscreen 3D test manages to draw more power on the new Nexus 7 than the old one, and that isn't taking into account the nearly 5x increase in performance on the new Nexus. In fact, as impressive as these numbers are - they are even more impressive when you take into account performance. To make a long story short, don't worry about the ~7% decrease in battery capacity as there are enough improvements in platform power and performance (and thus perf per watt) to more than make up for the smaller battery.

We'll start out with our WiFi web browsing test. Like all of our battery life benchmarks we run this test with all devices calibrated to 200 nits and connected to 5GHz 802.11 WiFi (if supported). The test itself cycles through a bunch of desktop websites at a very aggressive frequency. Our test ensures that both the CPU cores and wireless stack can reach their deep sleep states during simulated reading periods. The test continues until the battery is depleted.

Web Browsing Battery Life (WiFi)

The new Nexus 7 does better here than any other small tablet we've ever tested. Remember that 50% decrease in idle platform power? That's exactly why we're seeing a 35% improvement in battery life compared to the original Nexus 7.

Our video playback test involves looping the playback of a 4Mbps 720p High Profile H.264 transcode of the last Harry Potter Blu-ray. All displays are calibrated to 200 nits.

Video Playback Battery Life (720p, 4Mbps HP H.264)

Video decode blocks are fairly well optimized to begin with, so there's not a ton of room for improvement here compared to last year's Nexus 7. Despite the ~7% shrink in battery capacity, the new model manages a 10% increase in battery life though. We also have the first small Android tablet capable of beating the iPad mini in a video playback test here - job well done ASUS/Google.

Our final test involves looping the Egypt HD benchmark until the battery is completely drained. Frame rates are capped to 30 fps to somewhat simulate actual gameplay and not penalize faster GPUs.

3D Battery Life - GLBenchmark 2.5.1

The new Nexus 7 manages to deliver slightly better battery life here despite driving higher frame rates and more pixels. Overall performance here isn't anything super impressive, the only average showing from the Nexus 7.

Google ships the Nexus 7 with an ASUS branded 7W charger, identical to the one you'd find in the box of a MeMO Pad HD7. Given identical chargers and battery capacities, there's no surprise the new Nexus 7 takes the same amount of time to charge as the MeMO Pad HD7 (~3.5 hours).

Charge Time in Hours

The new Nexus 7 also supports wireless charging by implementing the Qi standard. Charge time is a bit slower wirelessly as Qi can only charge at up to 5W. Brian tested Qi functionality in his mini review of the Nexus 7 and didn't have any issues.

Introduction & Display CPU & GPU Performance
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  • iampivot - Saturday, August 24, 2013 - link

    Is the GSM modem on the 4G / LTE version locked down, so that you cannot make calls nor send SMS messages, like the original nexus 7?
  • Shukla - Saturday, August 24, 2013 - link

    Is it me or is this about 1 year behind iPad? So google puts out an iPad 4 competitor 1 year later??

    I'm no apple junkie but why is it that each year apple resets the bar and everyone spends the year catching up but not passing in everyway?

    1. No individual app privacy controls
    2. Longer battery life than iPad/iPhone (by wide margin).

    I need a job with google marketing- they suck.
  • GTBandit22 - Saturday, August 24, 2013 - link

    Well considering this is a 7 inch tablet, and half the cost of the entry level iPad, I would say you're making a bad comparison.
    I would say that Apple is behind in the small form factor race. 6 months behind.
  • akdj - Sunday, August 25, 2013 - link

    Possibly because the released (Apple) their tablet nine months ago? It'll never end. They're working six months apart. With each company's current release, it'll 'best' the six month old competitors. Technology, especially low power SOC and GPU designs are developing at a rapid pace. Give it a couple months and we'll see the same thing happen with Apple's new lineup. In fact, the iPad 4 is still holding is the iPhone 5 to the current crop of Android releases (other than extreme screen sizes). I like what Google is now doing with their Nexus series. Like Apple, they're designing (or helping design) the hardware and optimizing their software to work efficiently together. Super smart decision without the carrier and OEM skins we've had to live with until these new Nexus tablets have released. Smart. Idea.
  • lightsout565 - Sunday, August 25, 2013 - link

    Can someone provide me a link with a more detailed outline of how the WiFi web browsing test is conducted? Thanks!
  • mikeyfouc - Monday, August 26, 2013 - link

    Can this plug into a VGA overhead projector to mirror the screen? I'd really like to get a tablet that allows me to show Powerpoint presentations on a VGA projector. I've seen AT's review of SlimPort, but it only has a video of the mirroring on a widescreen HD TV via HDMI. Also, I've searched all over the web: can Android show powerpoint presentations in slideshow mode (as you'd see on a PC)?
  • Shopov - Tuesday, August 27, 2013 - link

    Excelent review! My question-Nexus 7 (2012) does not support WiFi Ad Hoc (ibss). This is boring since its only WiFi version (no LTE) cannot receive WiFi from tethered smartphone (mine is Nokia C-7). What about the WiFi of the new Nexus 2013? If the answer is positive this would be a big advantage. I should mention that several Android 4 tablets receive WiFi Ad Hoc (ibss).
  • Nexus 7 2013 - Thursday, August 29, 2013 - link

    For anyone considering this device, please check out the forum on Google :!topic/mob...

    Majority are as reviewed, but a small, yet growing number are effected by software/hardware issues that, after a month's time, are yet to be concretely dealt with.
    Buy only from a vendor having a good solid return/exchange /refund policy.
  • Hrel - Thursday, August 29, 2013 - link

    No 802.11ac?! Lame.

    "The beauty of not having to double the original Nexus 7's resolution but instead settling on an in-between option like 1920 x 1200 is that Google could get away with a performance mainstream SoC instead of something ridiculously high-end."' ... what? That's a ridiculously high resolution, Apple is stupid for thinking a resolution that high is useful.

    I'd like to see them go 16:9, make the device 8" and give it a 1920x1080 display resolution. Perhaps next year, with 802.11ac.

    With that said, I can't see myself even entertaining the idea of actually buying a tablet unless it's gaming focused like the Nvidia... thingy...I forget the name.

    This is how I see it, tablets are secondary for web browsing in the first place, anyone in their right mind prefers using a laptop. Which, let's face it, anyone who can afford a tablet already has. So, WHY would someone buy a device where the primary focus is web browsing? Give me a tablet that's focused on mobile gaming (PSP/gameboy style) that also has all the functionality of one of these tablets, web browsing. I think Nvidia is on the right track, streaming desktop games so you can lie in bed and play without having a laptop on your chest and your wrists angled awkwardly. Play mobile games when away from home/on a plane/cab. Also allows you to read ebooks and listen to audio books AND check facebook/reddit/anandtech/twitter whatever, newegg and amazon and such.

    I think if Nvidia just keeps doing what they're doing they're next gen "tablet" could be the perfect device. The only recommendation I'd make is to choose to focus on making it as good a mobile reader as an IPS display can be, it won't ever be as good as a kindle with that Eink display, but if it's close enough, and they can produce numbers to show no meaningful eye strain then I'm sold. They've gotta compete with Razer Edge, or whatever, too.
  • justacousin - Tuesday, September 3, 2013 - link

    So what is going to be Nexus devices in improving their device?

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