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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  • RYF - Thursday, August 22, 2013 - link

    It is always important to benchmark and compare against the best-selling 7 inch tablets. What is the point of comparing N7 against the half-hearted efforts shown in the recent Galaxy Tabs?

    I am not a fan of iOS. But I have to state that iOS is still, by far, the easiest mobile OS to be used by the majority.
  • Impulses - Friday, August 23, 2013 - link

    It's not even about that, I appreciate the comparison too despite wanting nothing to do with any iOS device... Apple is still a premium hardware company so the comparisons ate entirely relevant. The day their devices aren't built up to snuff or their market share falls as far as Mac share has at times then the comparisons become irrelevant.
  • Impulses - Friday, August 23, 2013 - link

    Besides, Anand can mention Apple every other paragraph and the general comparison is still more unbiased (not to mention the review more in depth) than the vast majority of sites can manage...
  • ESC2000 - Wednesday, August 28, 2013 - link

    I don't think the person complaining about Apple bias in this article is referring to the fact that the benchmarks included ipads. I think they are referring to the comments like (I'm paraphrasing) 'the new nexus is a downright Apple way to rev a product' as well as the constant comments about how aluminum is premium.

    People want to hear comparisons to the competition in reviews but it doesn't make sense for the review to be touting another product. No more backhanded compliments please ('a downright Apple way. ..').
  • lmcd - Thursday, August 22, 2013 - link

    I came out of this review with "there's no way in hell to buy an iPad Mini right now and feel good about yourself."

    So, link me to what you just read please?
  • sweenish - Thursday, August 22, 2013 - link


    This review in no way made me think that an Apple tablet was more deserving of my money.
  • jeffkibuule - Thursday, August 22, 2013 - link

    Considering Apple's tablets are 9 months old at this point, is there any different conclusion a reasonable person should make other than wait?
  • ESC2000 - Wednesday, August 28, 2013 - link

    I didn't wait. Whatever Apple releases I know it will cost more and probably have less than the nexus 7 2013... or maybe it will be equivalent to the nexus and cost 2x as much and charge $100 for each 16 GB increase in storage ($40 for 16 GB increase on the nexus) not to mention $150 extra for cellular.

    Seriously what is there to wait for?
  • smartypnt4 - Thursday, August 22, 2013 - link

    Obvious troll is obvious.
  • Diorarat - Wednesday, October 2, 2013 - link

    No offence but I'm not catching on what you mean by biased. Well what can you compare the N7 with the other than the iPad. You have to compare it with something and the iPad is definitely the best comparison. There are great android tablets in the market but I don't think they're as familiar to the consumers as the iPad. Besides, I think Anand is being fair to praise hardware that is excellent whether apple or android.

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