Battery Life

If there’s ever been an Achilles heel to the Surface lineup it’s probably been battery life. The thin and light form factor powered by the same components in most laptops means there just isn’t the physical volume for a really large battery. The Surface Pro 4 offered just 39 Wh of capacity, although thanks to some miniaturization, last year’s Surface Pro was able to bump that to 45 Wh. For 2018, that capacity is unchanged at a rated 45 Wh, although the battery is slightly overprovisioned showing just about 48 Wh out of the box. It’s still well off the 60 Wh that you’d find in a typical Ultrabook, but it’s much closer than just a couple of generations ago.

The other side of the coin is efficiency. With each generation of device, it’s not uncommon to see some small gains here as well.

To see how the Surface Pro 6 fares, we’ve put it through our suite of battery life tests, which we run with the display set to 200 nits on all devices.

2013 Light

Battery Life 2013 - Light

Our test from 2013 we’re keeping around just because of the number of datapoints we have now, but this test has become too light for most devices. Still, the Surface Pro 6 has cracked the 10 hour mark in this test. It achieves 1.25 hours more battery life than the outgoing model, which is a pretty strong result.

2016 Web

Battery Life 2016 - Web

Our newer web test is much more demanding on the devices, and the Surface Pro 6 does admirably again. At just over 9 hours of battery life, the Surface Pro 6 achieves almost two extra hours of battery life compared to the 2017 model. That is a big gain considering the battery capacity is unchanged from 2017.

Normalized Results

Battery Life 2013 - Light Normalized

Battery Life 2016 - Web - Normalized

By removing the battery capacity from the equation, we can get a measure of how efficient each device is.

The Surface Pro 6 is right at the top in terms of efficiency on our heavier 2016 test, and a hefty step up over the 2017 model.

Despite the smaller than laptop battery capacity, the overall results are quite impressive, with the Surface Pro 6 improving quite a bit over the previous model, although we did test that one with the Core i7 which can be a factor. Still, the overall results are very strong, with the Surface Pro 6 well over the eight hours of battery life that we’d want in a mobile device.

The Surface Pro 6 draws right around 5 Watts of power at 200 nits brightness with the system at idle, and that drops to just 1.22 Watts with the display off, so the system isn’t using very much power at all.

Movie Playback

Battery Life Movie Playback

Microsoft’s battery life claims on their specifications page for any of their devices always states battery life during local video playback. We test that as well, since it’s a common scenario for any portable device, but this is generally a best-case situation, since the video decode is offloaded to fixed function hardware, allowing the processor to go to sleep for much of the time.

The Surface Pro 6 was able to get just over 13 hours of video playback at 200 nits brightness, which is very close to the rated 13.5 hours that Microsoft quotes, although they are likely testing at a lower brightness level.

Battery Life Tesseract

Our Tesseract score divides the movie playback time by the length of a long movie – The Avengers – to give a nice number for how many movies you can watch on a device before the battery is depleted. The Surface Pro 6 was able to get through over 5.5 copies of The Avengers on one charge.

Charge Time

The Surface Pro 6 comes with the standard Surface charger, which we’ve become accustomed to over the years. It connects to the Pro with a magnetic connector on the with what Microsoft calls the SurfaceConnect port. For the Pro 6, it comes with a 44-Watt adapter which also offers a USB port for charging another device, which is very handy.

Battery Charge Time

The charge times are pretty standard for the class of device, with very few manufactures pushing for really fast charge times on laptops likely to increase the longevity of the battery.

Display Analysis Wireless, Audio, Thermals, and Surface History
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  • Speedfriend - Tuesday, October 16, 2018 - link

    For all the talk of a lack of innovation from Intel, the charts comparing the various generations are quite incredible. 60% improvement in single threaded, 175% in multi, combined with a 100% improvement in battery life.

    Microsoft has got a winning device here, I see more Surface Pros at conferences than any other type of laptop including Macs, though still behind iPads
  • fallaha56 - Tuesday, October 16, 2018 - link

    you’re bigging up numbers from years and years ago....
  • vanilla_gorilla - Tuesday, October 16, 2018 - link

    I'm guessing these are Microsoft conferences? Not sure where you're seeing more Surface devices than Macs or Thinkpads or HP laptops. Surface sells in incredibly small numbers compared to those other manufacturers. And what conferences have more iPads than anything? I'm not sure if you're lying or if you're attending conferences selling timeshares to senior citizens?
  • althaz - Wednesday, October 17, 2018 - link

    You're just wrong here. Apple definitely sells more than Microsoft (Lenovo is around the level of Apple with HP and Dell far outstrip the rest). But the different isn't huge. There's no world in which "Surface sell in incredibly small numbers" compared to any other manufacturer's line.

    When you are talking about premium laptop-ish devices, the Surface line is comparable to the other popular makes. It's smaller than the top 4 - but in its category not by all that much.
  • melgross - Wednesday, October 17, 2018 - link

    I don’t know what conferences you go to, other than those for IT, but I’ve never seen one of these anywhere.

    With all of the talk about these, as though they’re really important, Microsoft still has to show that they can grow yearly sales beyond the 3 million (maybe!) they barely managed so far. With SurfaceBook sales lower than 500,00 a year, and the Surface PC supposedly in the tens of thousands a year, none of these lines are doing anything near well.
  • TheinsanegamerN - Wednesday, October 17, 2018 - link

    Except that speed increase comes from lower power usage. At the same clocks, intels chips are still not any faster then 3 years ago.

    Yeah, great, you went from "slow" to "decent speed.". The iGPU is still no faster, max performance is still dependent on the cooling system, and anything that isnt restricted to CFL light-bulb power levels is no faster.
  • name99 - Wednesday, October 17, 2018 - link

    Looking at this sort of improvement misses the reason for concern with Intel.
    The original CPU (i3-4020Y) is 1.5 GHz, no turbo.
    The end point CPU (i7-7660U) is 2.5GHz base, turbo to 4GHz.

    Now from one point of view, it's nice that Intel has managed to boost frequency this way while not moving too far outside the power envelope. That helps low power devices (like Surface!) AND it helps large core count server chips.

    BUT look at the larger story. It's about lower power, NOT about higher achievable frequencies. The tech that got this does not help that much in boosting the frequency of your 120W desktop CPU in single-threaded mode. Meanwhile, there's been very little improvement in IPC, which can improve performance at the high end.

    If you care about some classes of devices, yes, great progress by Intel. But if you care about single-threaded performance at the high end, what's shown here is irrelevant, and just highlights that Intel either through inability or lack of interest is not delivering anything close to the same improvements at the high end.
  • GreenReaper - Friday, October 19, 2018 - link

    The original was a i5-3317U dual-core hyperthreaded 1.7Ghz -> 2.6Ghz turbo. I have one. It's still quite nice, although with the cooling it has it can only maintain ~1.9Ghz under full load with BOINC.

    Surface Pro 2 and 3 were significant steps back in terms of single-threaded performance, to achieve the "thin and light" goal and improve battery life. That was probably the right decision for the target audience, but given I use my Pro 1 as a second screen I'm glad I got it cheap when the Pro 2 came out.
  • Eliadbu - Friday, October 19, 2018 - link

    The days of CPU improvement are near the end
    IPC improvement is near the limit adding more instruction to the already large CISC is doubtfully helpful. We are just about the end on how far we can push the clock speed and and adding more cores and threads is useful but to a certain degree. And this is also true for AMD. A new direction should be taken like instead of stack of general purpose CPUs for a all consumers a family of specialized CPUs would good idea.
  • wr3zzz - Tuesday, October 16, 2018 - link

    What is the downside of using a U-class CPU without active cooling? Surface Pro i5 is not the only one. Huawei's Matebook also pairs U-class 15Watt chips without fans.

    Why won't more companies do this?

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