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 installed the latest Intel drivers on the VAIO Pro 13 for testing before the initial review, which is something we do on all laptops. I don't know if the Sony-provided drivers would have changed things, but it's possible.
  • MarcAnton - Monday, October 21, 2013 - link

    Thanks. Was not trying to invalidate your results, it just stems from my experiences with Sony Vaio drivers for my Sony Vaio Series S (SA) under Windows 8.1. Most drivers are not even updated for Windows 8.1.
  • JarredWalton - Monday, October 21, 2013 - link

    No worries. Installed drivers right now are 15.​33.​5.​3316 -- I think that's the latest from Intel as of last week. The previous battery life testing was completed with the earlier 15.​31.​17.​3257 driver. Maybe that accounts for the change in the Medium test result, but I'm retesting now just for validation....
  • Rainbird01 - Monday, October 21, 2013 - link

    That would be very welcome as well. I don't know how far from the release the Modern VLC app is, but it might interesting to compare it to VLC on the desktop.
  • skiboysteve - Monday, October 21, 2013 - link

    Jarrod the video windows store app uses entirely different rendering APIs do I imagine the difference would be dramatic.

    another thing to keep in mind is desktop and all its baggage is not loaded until you tap the desktop tile. So you might get different results if you never tapped it after boot or if you did
  • JarredWalton - Tuesday, October 22, 2013 - link

    Trying to avoid the desktop is essentially impossible and I seriously doubt it's not loaded until used. Think about all the stuff that's on the desktop: Windows Explorer is one, most of the control panel stuff, any non-Modern app, Task Manager, etc. If you had to wait a few extra seconds for a bunch of "baggage" to load you would know it. Even browsing through a file open dialog in a Modern app is likely to use parts of Windows Explorer, so I would bet the desktop is always present in some form with Windows 8. In fact, testing that I did previously indicated that Modern Apps (Music and IE10 at the time) both were less power efficient than the "baggage" desktop IE10 and Windows Media Player -- and the Modern Apps always seem to take way longer to load than they should.
  • skiboysteve - Tuesday, October 22, 2013 - link

    Jarrod, yes, according to Microsoft the desktop code is not loaded (in its entirety) unless you enter the desktop at least once. See here:
    "You can use only new apps and never leave them if you want (in which case all of the desktop code is not even loaded.) "

    I can attest to this because I have a HDD in my desktop running win 8 and now 8.1 and if I hit the desktop within a few hours after boot it takes a while and hard drive banging to load.

    I also know that WMP and the Video modern app use different APIs to render video. You can see this in the task manager. one is called protected video pipeline and the other is something else. Back when I had a radeon 4850 in my desktop I had a driver bug where the modern video apps like netflix, hulu, and xbox video would leak ram and crash hard after a while but windows media player of VLC did not. Later I got a geforce card and all is well. This shows it is tied to WDDM more closely so I would assume better battery life
  • tipoo - Monday, October 21, 2013 - link

    It's worth mentioning too that this Vaio seems to fly in the face of the running theory that Windows is inherently bad at idle/light load battery life, and proves it's more down to manufacturers.
  • JarredWalton - Monday, October 21, 2013 - link

    Oh, it's almost entirely up to the manufacturers in my opinion -- maybe it's a bit more difficult to do with Windows than say OS X, but it *can* be done. Sadly, even laptops from the same manufacturer can have issues -- so the VAIO Pro 13 is really good on battery life, but perhaps another Sony has issues. Sony is usually pretty good about optimizing for battery life, but HP, Dell, ASUS, etc. are highly variable depending on the model. Budget laptops rarely get any TLC in terms of BIOS/firmware optimizations for example.
  • tipoo - Monday, October 21, 2013 - link

    I bring it up because this codinghorror article is making its rounds around the internet, and everyone seems to just "know" windows is the culprit. But this seems like pretty clear evidence that is not the case.

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