Battery Life and Charge Time

On most notebooks this section is one of the most important, but on a machine like this, portability takes a back seat to performance. There is still the expectation that you can have some battery life, but with the understanding that all of the components inside which make the Phobos 8716 so fast come at a cost of power consumption.

That is certainly the case if the machine is being stressed. With a CPU featuring a 91-Watt TDP, and a GPU which has an undisclosed (but under 180-Watt) TDP, the battery capacity of 82 Wh can be exhausted pretty quickly. But if you do need to use the notebook off the mains, having the ability to watch a movie, or surf the net a bit would be nice.

To test battery life, we have two main tests. Our older 2013 light battery life test loads four web pages every minute, and the test continues this until the laptop stops. The newer 2016 battery life test leverages the same test we use on mobile, which is much more stressful. There is no perfect way to measure battery life, since everyone’s use case is different, but by providing consistent testing with the displays set to 200 nits, we can at least get a good comparison across devices on a common usage scenario.

One note about this laptop is that despite being set to not change the display brightness, when the battery hits 7%, the brightness drops to zero, meaning this laptop will score a few extra minutes than it should.

2013 Light

Battery Life 2013 - Light

On our older battery life test, the P870DM2 / Phobos 8716 does surprisingly well. It achieves a result of just under three hours, which is terrible compared to an Ultrabook, but compared to the previous Clevo DTR, there is a pretty significant jump. Since the battery size is the same between the P750ZM, albeit the older model does have a UHD display which would certainly impact the result. Still, it’s a reasonable result.

2016 Web

Battery Life 2016 - Web

With the new web test, which is much more stressful to the CPU, the Phobos 8716 actually scores a few minutes higher than on the older test. The average power consumption doesn’t change much despite the increased workload. That isn’t a big surprise when you have high power components, since their baseline power usage will already be a lot higher than something meant for long battery life like a Cherry Trail Atom, where every milliwatt matters.

Normalized

To give an actual value to efficiency, the battery size is factored out of the battery life to provide a minutes / Wh result.

Battery Life 2013 - Light Normalized

Battery Life 2016 - Web - Normalized

Unsurprisingly, with desktop components stuffed inside, the Clevo P870 DM2 is one of the least efficient notebooks tested, with only the Clevo P750ZM being worse. Better is better, but the target use case for this machine is not an all day battery powered notebook, so it’s not as big of an issue as it would be on smaller laptops.

Additional Battery Life Testing

OK, so we’ve already determined that the Clevo P870DM2 is not the world’s best notebook in terms of battery life, but there are a couple of other scenarios which warranted testing. Since it’s a gaming notebook, just how long can you play while gaming? To test this, Tomb Raider was fired up, and it was configured to use the Battery Booster settings with NVIDIA’s GeForce Experience (GFE) software.

Battery Life Rise of the Tomb Raider

The settings in GFE capped the frame rate to 60 frames per second, exactly. Minimum was 60.0 frames per second, average was 60.0 frames per second, and maximum was 60.0 frames per second. The result was being able to play Tomb Raider for just over an hour. With a bit more tweaking, and adjusting the GFE a bit, maybe a few more minutes could be eked out, but the runtime of one hour gaming is pretty decent. Plus, you get the added benefit of the fans barely spooling up since the notebook isn’t even working hard.

The other potential reason to need battery life is when watching a movie. Perhaps you are on a road trip and you have your 12 lb laptop in your lap. Can you get through one movie? Two? Let’s find out.

Battery Life Movie Playback

The result playing a movie is not that much better than surfing the web. On Ultrabooks, this task is offloaded to fixed function hardware, and it can increase the battery life significantly, but the idle power usage of the Clevo P870DM2 is just too high for this to make much of a difference.

To put this time into perspective, we’ve come up with a new movie battery life rating which we have deemed the Tesseract. Each Tesseract equals 143 minutes, or the length of The Avengers movie.

Tesseract

You can easily get through one run of The Avengers, but only through 40% of a second run, so unless you love cliff hangers, you may want to find somewhere to plug in.

Display Wireless, Audio, Thermals, Noise, and Software
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  • ZeDestructor - Thursday, October 27, 2016 - link

    Picture of the innards clearly shows one MXM module populated with an empty slot for a second MXM module. With two MXM cards installed, the heatsink for each GPU is shrunk by half though (second card takes over the second fan and gimps the first card to only having the leftmost fan), so there will be a lower boost max. Reply
  • Glaurung - Thursday, October 27, 2016 - link

    "Let's be real, you aren't moving this thing around. Just buy a desktop."

    A laptop takes up much less room than a desktop, and you can close the lid and stow it away in a drawer. Whereas a desktop is always going to be hogging space on your desk for its keyboard, mouse, and monitor. For someone with a small apartment or student dorm room, the ability to simply close the lid and stow the whole thing away is a huge benefit. Don't think of this as a battery powered portable computer, think of it as a compact, stowable computer that has a built in UPS.
    Reply
  • andychow - Thursday, October 27, 2016 - link

    While I agree with the statement that many buy laptops to be able to stow the thing away, this is a $2255-$5000 device. It's not something I would imagine people in small apartments or dorms would get. Then again, I see "poor" students with macbook pros all the time. You have a good point actually. Reply
  • nerd1 - Sunday, October 30, 2016 - link

    Many students I know pay >70k for just tution and rent. $2500 laptop is not that expensive in that regard (especially compared to macbook pros with the same price range) Reply
  • Morawka - Thursday, October 27, 2016 - link

    12 pounds for that model, its still a lot easier than lugging around a tower, monitor, cables, etc..

    this is a great mobile VR Rig.a
    Reply
  • DanNeely - Thursday, October 27, 2016 - link

    Do you have any power usage figures? I'm curious what the TDP for the mobile version of pascal is. A Desktop 1080 is 180W, did manage to knock 80W of the mobile card to match the outgoing 980m despite only dropping the clock rate a few percent (massive binning???), or is near desktop performance equivalence coming at a huge expansion in power consumption? Reply
  • BrokenCrayons - Thursday, October 27, 2016 - link

    You can do some quick estimations based on the fact that the SLI version requires two 330W power supplies.

    Add to it the cooling configuration of six heat pipes and two radiators...but we need to go back a bit to older tech for the heat pipes. A Dell Latitude D630 with an Intel x3100 GPU has a single heat pipe for the chipset and 35W processor's cooling needs. Assuming the pipe design is better means that a single heat pipe can likely handle 45W total TDP and that's a pretty reasonable estimate, but let's be conservative and say one pipe can deal with only 30W TDP. 30 x 6 pretty much means 180W TDP for the mobile part. Take into account the GPU can't sustain a full load at its highest clock even with all that cooling capacity and I think we're looking at a mobile GPU with the same TDP as the desktop part. There's certainly a lot of compelling evidence pointing that way anyhow.
    Reply
  • DanNeely - Thursday, October 27, 2016 - link

    Full desktop power is certainly possible, but the need for a second power brick doesn't prove much beyond >~110W. 90 (CPU) + 30 (everything else) + 2x110 = 340W which would max out the 330W power brick.

    I don't think your handwaving with the heatpipe count argument holds any strength, the size of the heatsinks on the other end, the power of the fans, and what temperatures are considered acceptable puts too much variation to try and assign an N Watts capacity to a single pipe and scale off of that.
    Reply
  • BrokenCrayons - Thursday, October 27, 2016 - link

    It's all extremely rough estimation on my part and I admit readily it's rife with possible faulty thinking and off-the-cuff guesswork, but unless or until we get credible numbers either from NV directly or from a group equipped to perform accurate analytics, there's nothing left but idle speculation...which can be sort of fun in its own way even if it ends up being way off the mark. Reply
  • Brett Howse - Thursday, October 27, 2016 - link

    Please don't forget that this also supports overclocking, so they have to supply a big enough power adapter to avoid running out of headroom when overclocking, so you can't really make the assumptions you are.

    NVIDIA doesn't have formal TDP numbers for the mobile parts, but they are going to be somewhere under the desktop ones.
    Reply

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