Update: Intel Expands Our Battery Testing At CES 2013

Tablet Two Ways: Deconstructing Battery Life Measurements

I started this story by telling you generalizations about battery life are potentially misleading, and then proceeded to make observations about battery life. What gives?

Well, we isolated two usage models that typically come up in our tablet reviews: web browsing and video playback. By measuring battery power over time across four devices under multiple scenarios, it’s possible to see how consumption changes depending on the specific workload. Moreover, we have examples of the placing order changing, again, dependent upon on the workload.

The reason we’re exercising caution should consequently be pretty clear. Reviews need to be explicit about what they’re using to generate battery life numbers. And even then, it’s only possible to draw conclusions about power performance in that one specific scenario. Running more or less demanding test cases will change things up, sometimes quite significantly.

Averaging the power consumption of all five tests suggests that the Qualcomm-powered ATIV Tab and Intel-driven W510 are roughly equivalent when it comes to power draw in web browsing and video playback. However, the individual benchmarks make it clear that specific workloads can exact much different demands. This will become an even more important discussion in the months to come as competition tightens and SoCs become more powerful.

The Tablet Space In 2013

It’s going to be an exciting year for smartphones and tablets, based on what we’ve seen during the first two days of CES.

First, we have Nvidia's Tegra 4, armed with its reference Cortex-A15 cores and newly-separated pixel and vertex shaders. We don’t have power or performance figures for it yet, but it’s easy to imagine a very power-friendly SoC at idle, and a power-hungry chip under even light load. In talking to Nvidia about its Shield gaming device, the company says it wouldn’t be unrealistic to achieve 24 hours of video playback from a 38 Wh battery pack. Even if you factored out all other platform components, the SoC would have to sip less than 1.6 W for this to be possible. That’s less than half of Tegra 3. In order to get the 5-10 hours of gameplay, Tegra 4 would need to run between 3.8 and 7.6 W. We're immensely curious to see if the company can do this.

Then we have the lower-power Atom processors composed of 22 nm transistors and low-voltage Ivy Bridge-based parts, which we might expect to apply pressure from both ends of the power band. Intel claims that its Haswell architecture will be exerting influence in the same space as quad-core Cortex-A15-based devices by the end of the year.

Moreover, Qualcomm impressed us with preliminary numbers on its Snapdragon 800 and 600 SoCs. Although the company’s CES announcement was light on specifics about what it altered in the Krait architecture to get additional performance from the CPU cores, we do know that clock rates are up. Additionally, the Krait 300 inside the Snapdragon 600 now include hardware data prefetch, better branch prediction, improved memory management, and a handful of other tweaks for higher performance in specific tasks. To those enhancements, the Snapdragon 800’s Krait 400 CPU incorporates a redesign to optimize for high-K 28 nm manufacturing, lower memory latency, and faster L2 cache.

At the end of the day, though, cranking performance up 40 or 75% is only meaningful if it can be done without negatively affecting power consumption. We’re not yet certain how Tegra 4 and Snapdragon 800 compare to their predecessors in that regard, but we do find it interesting that Intel is the only company eager to illustrate the power of its designs in a lab setting. By picking up the torch and granularly tracking the consumption of individual subsystems, we hope we can shed some light on the strengths and weaknesses of each respective architecture as they surface in the next generation of tablets and smartphones.

Stay tuned to our CES 2013 landing page as we continue covering the year's biggest consumer electronics trade show.

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  • amuffin
    Strike a pose for the camera!
  • archange
    Are there any news about the 5th companion core in Tegra being supported under RT? Is software patching feasible?
  • abbadon_34
    Please tell me the "Metro" reference in IE10 does not mean some forced Win8/Metro style interface. They've lost enough users to other browsers, do they want the rest to jump ship?
  • tomfreak
    whatever it is, 5-10hours of battery life is not good enough. 24hours is the ideal length.
  • archange
    abbadon_34Please tell me the "Metro" reference in IE10 does not mean some forced Win8/Metro style interface. They've lost enough users to other browsers, do they want the rest to jump ship?


    It's not "forced". On w8 you get applications specifically designed for touch input. Basically, you have two versions of IE10: the "regular" desktop one and the "Metro" version. The latter has re-placed the URL / search bar at the bottom and has larger, finger-friendly buttons. It also hides its bars for a full-screen browsing experience, which comes in handy on smaller tablet screens. Oh, and I don't use it. Dunno why, but it just doesn't appeal to me :P
  • vaughn2k
    AMD should never had sold the (Imageon) Adreno to Qualcomm.. they should have been gaining business in the mobile business by now... Ruiz was a @*!!@$$...
  • ojas
    Also an interesting read:
    Anand's pre-CES article b/w Atom, Krait and the Cortex A15:
    http://www.anandtech.com/show/6536/arm-vs-x86-the-real-showdown
  • ojas
    Was interested to read about the predictions for this year.

    Quote:
    In order to get the 5-10 hours of gameplay, Tegra 4 would need to run between 3.8 and 7.6 W. We're immensely curious to see if the company can do this.

    Anand estimated a 8w TDP for a quad core A15, i think it was the Exynos....with that in mind...i think you're indeed right about your estimate...

    The yellow line is the time he's gaming.

    Quote:
    Intel claims that its Haswell architecture will be exerting influence in the same space as quad-core Cortex-A15-based devices by the end of the year.

    True...Ivy Bridge's already dipped to 7w...
  • kyuuketsuki
    So... you list those 3 SoCs as defining the 2013 tablet space and completely ignore:

    1) Samsung's A15-based Exynos
    2) AMD's Temash

    The heck?
  • cangelini
    KyuuketsukiSo... you list those 3 SoCs as defining the 2013 tablet space and completely ignore:1) Samsung's A15-based Exynos2) AMD's TemashThe heck?

    We didn't have that hardware on-hand in Vegas, but certainly would like to add those numbers!
  • mayankleoboy1
    The only noteworthy point i see here is how much Tegra3 sucks.
    Makes me wonder what the hell was MS thinking when it chose T3 as the heart of their main product, and a showcase of WinRT. Has MS management gone completely crazy ?
  • mayankleoboy1
    Is there any way these tests can be repeated, but with Android as the OS ?
  • mayankleoboy1
    ojasvy Bridge's already dipped to 7w...


    That was marketing BS. FUD 101.
    Read the updated reports, which clearly say that those chips are 13W really.
  • mayankleoboy1
    @ Chris Angelini :

    Did they give all that power measuring equipment to you for keeps ? Or was it only for the CES ?
  • thety6on
    Hahaha nice job with the picture, Tom's. I love Hemingway