Last week I finished up the review of the Sony VAIO Pro 13, which delivers excellent battery life compared to most other laptops that we’ve tested – granted, it’s also one of the first Haswell ULT systems we’ve tested as well. Shortly after the review posted, Microsoft officially released the Windows 8.1 update. Battery life is apparently one of the areas that’s supposed to improve with Windows 8.1, or at least that’s the theory. I reran the battery life tests (only with the internal battery, in order to keep testing time manageable), and here are the results:

Sony VAIO Pro 13 Battery Life (Minutes)
  Windows 8 Windows 8.1
Light 481 479
Medium 315 283
Heavy 195 191

I’m going to have to rerun the Medium test (after the battery finishes recharging yet again), just to verify the result, as it shows a rather significant 11% drop compared to my initial testing. (Update: a second run confirms it; I don't know why, but the Medium test is definitely getting worse battery life now.) As for the other two tests, they’re also down compared to the earlier results, but here we see a 2% drop in the Heavy test and only a 0.4% drop in the Light result. A margin of error of ~2% is normal for battery life testing, so short of retesting multiple times I’m willing to call the Light and Heavy results a tie.

The main takeaway here is that anyone expecting Windows 8.1 to dramatically improve battery life relative to Windows 8 is likely going to be disappointed. Note that we do test with the LCD at a constant 200 nits, so optimizations that turn off the display sooner rather than later could still have an impact, but in comparing equivalent settings we did not notice any improvement on the VAIO Pro 13.

Far more important in my experience will be the laptop BIOS/firmware. I’ve been communicating with Intel recently in the hope of helping to improve the situation, as I have a few Haswell-equipped laptops that are failing to deliver the expected battery life. If all goes well, Intel will bang some OEM heads and we’ll get BIOS updates that will improve our battery life.

Frankly, I’m amazed that some companies still appear to not put in the necessary time/effort to deliver good battery life. Clevo is probably my biggest gripe right now, and we’ve dinged them on battery life for as long as I can remember. With the Haswell Clevo notebooks that I have right now (P157SM and W740SU), it appears neither one is using the deeper sleep states (C6/C7) for the CPU package – and in the case of the P157SM, it’s not even using the package C3 state. The CPU cores are properly using C7, but the package is not. That may not be the only item holding back battery life, but at least it appears to be part of the puzzle.

In short, consider this a warning shot across the bow of the laptop manufacturers. It’s time to join the modern world, and failing to put unused devices to sleep or to take advantage of deeper sleep states with computer hardware is not acceptable, especially on a laptop. I don't want software hacks to turn off the display more quickly, or drop the brightness to 100 nits in direct sunlight; I want real improvements. Besides raw battery life, I'll at least be checking to see that future laptops use all the available C-states (on the cores as well as the CPU package) when running off the mains.

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  • JarredWalton - Monday, October 21, 2013 - link

    I'd have to see if Anand used the "Balanced" or "Power Saver" setting for his Surface Pro 2 review, but it may have been Balanced -- which would mean it would a bit closer to the VAIO Pro 13 result on Power Saver. Also, Anand used our tablet battery life test, which at one point was less demanding than our laptop battery life test but perhaps the latest iteration changed things -- and depending on whether he used IE10/IE11 in Win8 mode or desktop mode, he could also see lower battery life.

    But there are definitely advantages for the OS X side of things. Someone mentions OS X getting timer coalescing and expecting another 10-15% improvement, but I don't think it will be more than 5%. My bet is OS X is so optimized for the hardware that short of reducing the LCD brightness or something along those lines, it's the maximum we'll see in terms of battery life. Anand ran the MBA13 2013 Haswell model on Win8 as well as OS X and also saw markedly improved battery life with OS X, but that's partly because Apple doesn't have any real need to optimize the Windows side of their laptop story.
  • jyotib - Monday, October 21, 2013 - link

    This article makes for painful reading - battery life for my own Vaio Pro 13 has taken a real hammering after the Win 8.1 update. The culprit seems to be screen brightness - it immediately stretches out to full brightness, regardless of whether the machine is onw balanced or low-power mode, on mains power or battery, and regardless of what the actual screen brightness setting is. any thoughts on sorting this out? What intel updates did you carry out, Jarred?
  • JarredWalton - Monday, October 21, 2013 - link

    I had the display brightness get stuck at one point, but a reboot fixed that. I have the latest Sony BIOS and updates from their VAIO Care software, and I have the latest Intel graphics driver. I don't think I did anything else noteworthy. Battery life is for the Power Saver profile, with the LCD set to 87% (200 nits). Incidentally, I did run a test on Balanced at one point and battery life dropped I think around 10%.
  • ananduser - Monday, October 21, 2013 - link

    I honestly didn't believe OEM optimizations could carry so much weight. The Vaio Pro, which shares the same chipset, resolution with the Surface Pro, sporting even a slightly smaller battery, simply slaughters the latter. One would assume that by controlling the hardware and software, MS would provide an incredibly tuned machine.
  • JarredWalton - Monday, October 21, 2013 - link

    Note that Anand used slightly different tests -- I will need to try and run his workloads to see what they do on the VAIO Pro 13.
  • teiglin - Monday, October 21, 2013 - link

    Thanks for your amazing responsiveness Jarred, I'm really looking forward both to the tests that Anand ran on Surface, and the video player comparison you mentioned above.
  • sorten - Tuesday, October 22, 2013 - link

    This is the first I've heard that Win 8.1 was supposed to improve battery life. What were they changing in order to optimize it? Improved low power state support? Thanks.
  • JarredWalton - Tuesday, October 22, 2013 - link

    I don't know -- someone posted a comment in the VAIO Pro 13 review and said, "I've heard 8.1 is supposed to further improve battery life" so I tested it and found that at best, battery life remained static and in at least one test it dropped 10% or more.
  • juhatus - Tuesday, October 22, 2013 - link

    Thanks for the article :)

    Ryan said it here:

    "Among other things, Windows 8.1 will ship with support for Intel’s Connected Standby technology for Haswell, Direct3D 11.2, and a revised DPI scaling mechanism that is better suited for driving the high DPI displays that are coming down the pipeline for both Ultrabooks and desktops."

    and that links to this about connected power states:

    Maybe we still need some chipset-driver from intel? did you install Sony's CPPC driver? (Intel Collaborative Processor Performance Control (CPPC) driver).

    I hope there's no feature differences between i5-4200u and i7-4500u nor newly available i3-4010u for SVP13.
  • JarredWalton - Tuesday, October 22, 2013 - link

    Connected standby is only of use in increasing battery life while the system is asleep -- it allows portions of the system to wake up, download updates, then go back to sleep. In our tests, we're always on and never shutting of the display, so connected standby is not applicable.

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