Battery Life

With the iPad Air Apple moved to a 32.4Wh battery, a significant decrease from the 42.5Wh unit in the 3rd and 4th generation iPads. The smaller battery doesn’t come with a change to Apple’s claim of 10 hours of battery life, which implies a reduction in overall platform power. I confirmed a substantial reduction in platform power in my crude measurements earlier in the article. Although it’s possible for the iPad Air to draw substantially more power than the iPad 4, our earlier power data seems to imply that it’s unlikely given the same exact workload. Our battery life tests agree.

We'll start with our 2013 smartphone/tablet web browsing battery life test. As always all displays are calibrated to 200 nits. The workload itself is hidden from OEMs to avoid any intentional gaming, but I've described it at a high level here.

Web Browsing Battery Life (WiFi)

Our web browsing workload came in at exactly 10 hours of continuous usage - an improvement compared to the iPad 4. Battery life on LTE was good as well, consistently delivering just under 10 hours of usage. The fact that both LTE and WiFi tests deliver similar results tells me that we may be bottlenecked by some other component in the system (perhaps display?).

I've been running the same video playback test for a while now, although we're quickly approaching a point where I'll need to move to a higher bitrate 1080p test. Here I'm playing a 4Mbps H.264 High Profile 720p rip I made of the Harry Potter 8 Blu-ray. The full movie plays through and is looped until the battery dies. Once again, the displays are calibrated to 200 nits:

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

Video playback battery life also improves slightly compared to the iPad 4. Apple’s battery life claims aren’t usually based around video playback, so exceeding their 10 hour suggestion here shouldn’t come as a shock. Apple’s video decode power has always been extremely low.

Our final cross-platform battery life test is based on Kishonti's Egypt HD test. Here we have a loop of the Egypt HD benchmark, capped to 30 fps, running on all of the devices with their screens calibrated to 200 nits.

3D Battery Life - GLBenchmark 2.5.1

Our 3D battery life rundown test shows a substantial improvement in battery life over the iPad 4. IMG’s PowerVR G6430, running a moderate workload, can do so more efficiently than any of the previous generation GPUs in Apple’s SoCs. Much like the A7’s CPU cores however, there’s a wider dynamic range of power consumption with the G6430. Running at max performance I would expect to see greater GPU power consumption. The question then becomes what’s more likely? Since the majority of iOS games don’t target the A7 (and instead shoot for lower end hardware), I would expect you to see better battery life even while gaming on the iPad Air vs the iPad 3/4.

Charge Time

The iPad Air comes with the same 12W USB charger and Lightning cable that we first saw with the iPad 4. Having to only charge a 32.5W battery means that charge times are lower compared to the iPad 3 and 4:

Charge Time in Hours

A full charge takes a little over 4 hours to complete. The adapter delivers as much as 12W to the iPad, drawing a maximum of 13.5W at the wall. I still think the sweet spot is somewhere closer to 2.5 hours but that’s another balancing game that must be played between charge time and maintaining battery health. It’s still so much better than the ~6 hours of charge time for the iPad 3 and 5.69 hours for the iPad 4.

WiFi & LTE Connectivity Usability, iOS 7 and the Impact of 64-bit Applications
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  • sna2 - Wednesday, October 30, 2013 - link

    wrong.

    Most flash sticks are eMMC and they operate at 100MB/s to 200MB/s which needs usb3.
    Reply
  • Kristian Vättö - Wednesday, October 30, 2013 - link

    Read speeds can easily exceed 100MB/s because reading from NAND is much faster than writing to it. Write speeds of 32GB or smaller flash devices can barely hit 40MB/s because the NAND itself can't write faster, and it's the write speeds that matter when syncing. Even if we're dealing with a full blown SATA SSD the write performance for 32GB models is around 40MB/s. Performance does scale with capacity so a 64GB or 128GB model will be faster but we are still far away from data rates over 100MB/s. Reply
  • fokka - Wednesday, October 30, 2013 - link

    this, so much. i'm always astounded when people bring up that they wanna see (e.g.) usb3 in their next mobile device. as if there are any current devices scratching on the 30MB-mark which would be totally possible with usb2, if manufacturers wouldn't insist on implementing bargain-bin nand and even shittier usb-controllers. Reply
  • FCsean - Wednesday, October 30, 2013 - link

    It would be stupid of them to put thunderbolt cables for iOS devices since more than half of the owners don't own a mac. USB 3.0 would be the way to go but not everyone has USB 3.0 so they're not yet wasting their money in manufacturing USB 3.0 cables since it's a lot more expensive to manufacture. I think it's two times more expensive. Reply
  • darkcrayon - Wednesday, October 30, 2013 - link

    Not only that, but am I the only one who rarely syncs large amounts of data at a time anymore with an iPad? Most of the sync is done wirelessly in small amounts over time. The only time I need a full many gig sync is when I upgrade devices or (extremely rarely) need to do a full wipe. Faster syncing would be nice but it's just not the daily process it used to be. Reply
  • Sushisamurai - Wednesday, October 30, 2013 - link

    ...yeah.... I don't know about u guys, but is wireless sync all the time now, either comp to iPad or iPad OTA with iCloud, wiping my device q3-6 months. I have no issues with restoring a full 32GB, and it's pretty quick... Down speeds of 10MB/s wifi, 40MB/s LTE (OTA for both), but if I were to sync via comp, a HDD to NAND is pretty abysmal speeds. Not to mention, if it was TB/USB3 u're going to have a thickness increase, and I'd rather not. Inductive charging, if u recall, is a slow, inefficient form of charging. I'd rather have my full 2A going into my iPad versuses drawing the same 12W but giving me the equivalent of 6W wirelessly. NFC and tablets? Okayyyyyyyy there. Reply
  • petersellers - Wednesday, October 30, 2013 - link

    Doubly stupid considering that thunderbolt runs on PCI express lanes and PCI express is not present in any of these devices Reply
  • ekotan - Wednesday, October 30, 2013 - link

    You can't have Thunderbolt without a corresponding Intel chipset, so forget about it on any ARM tablet. Also, the NAND used by these devices is so slow that having Thunderbolt would be utterly pointless. Most can't even saturate USB 2.0, never mind USB 3.0. Only the most recent Apple mobile devices have NAND fast enough to saturate USB 2.0. Reply
  • abazigal - Saturday, November 2, 2013 - link

    I restored my 5s recently (coming from a 32gb 4s). The whole process took 1-2 minutes at most. Just plug in and click a button. Likewise, few people are so fastidious as to back up their devices via iTunes manually every day. The time savings from going thunderbolt is so minimal that unless your life somehow revolves around restoring thousands of these devices every day, I don't feel the benefits are worth the added cost. Reply
  • iSayuSay - Sunday, November 3, 2013 - link

    And how Thunderbolt sync would help? Did you realize how much is the transfer rate from NAND flash in the iPad/iPhone? No more than 16MB/s, it's not SSD per say. It's a slow internal memory it becomes bottleneck. So as long as Apple do not change those (I doubt it will ever for the next 5 years), there's no point of porting Lightning to Thunderbolt or even USB 3.0 .. Ever. Reply

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