Dell XPS 15 Haswell Edition: QHD+ with a Refined Design
by Jarred Walton on March 6, 2014 7:00 AM ESTDell XPS 15: Battery Life
Our final set of tests is for battery life, and here again we have a change or two to make. I did run our 2013 battery tests, but for 2014 I’ve made some changes. First, our “Heavy” test will now use the Windows Video app to play back a 1080p MP4 movie – the use of MKV files basically resulted in lower battery life by a fairly large margin, and MP4 files are readily available. I’m also considering dumping the “Moderate” workload and just sticking with Light and Heavy testing, as well as including approximate gaming battery life. There’s this mentality of “more information is always better”, but by the same token more information and testing means more time and thus less timely reviews. In general, our Medium battery life results have been pretty consistent about falling half way between our Light and Heavy tests, and with the newly modified Heavy test it’s just one extra benchmark with questionable value.
With that said, we continue to test with LCD backlighting set to 200 nits, WiFi is enabled, and earbuds are connected to the headphone jack. For the XPS 15 QHD+ display, 200 nits ended up being at exactly 50% brightness, which makes things easy on us. I do like that Dell has relatively consistent steps between backlight levels of around 35 nits per 10%. Many laptops that I’ve used in the past have been far less granular, sometimes going from 300 nits at 100% to 200 nits at 90% and then 10 nits intervals from there down to 0%.
Thanks in a large part to the 91Wh battery, the XPS 15 is able to place quite far up our battery life charts in terms of raw unplugged time. It’s not quite so awesome when we look at the normalized Min/Wh figures, but while that can be useful information at the end of the day people are going to be using the battery they get with this laptop. We measured nine hours of battery life in our light workload, nearly 6.5 hours in our moderate workload, and around 4.5 hours in our heavy workload.
Interestingly, our new Heavy test using the Video app with a lower bitrate 1080p MP4 results in battery life that’s basically the same as our previous Medium testing – so with Video, playing a fullscreen MP4 while streaming 1MBps and loading Internet pages every ten seconds isn’t really any more taxing than playing back an MP3 while surfing the web. It appears Microsoft's Video app can scale content without incurring a power penalty, whereas when I was using Media Player Classic previously higher resolution displays often did worse (e.g. look at the XPS 15 results above).
Trying to game off the mains is a different matter, however, and even with a relatively large battery the XPS 15 only manages less than two hours while running Skyrim. (If you’re wondering, for testing gaming battery life, we use the Balanced power profile with the GPU set to “Prefer Maximum Performance”. Then we load up our Skyrim save in the town of Whiterun and let the system run until the battery is drained. The camera begins to pan around the character so it’s at least moderately demanding, though other games are certainly more so.)
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oleguy682 - Thursday, March 6, 2014 - link
I understand the desire for 16:10 in place of 16:9. But if both are 1800 lines, do you really notice the missing 200 pixels at the bottom? I realize that the AR will resize a displayed window slightly, but it would be interesting to see the actual difference between what is displayed on 16:10 vs. 16:9 on a similar document or webpage that is scaled appropriately for the AR. Unfortunately my 4:3 screen only will give me a 16:10 or 5:3 (16:9.6 or so) AR so I can't really make the comparisons myself.Fox5 - Thursday, March 6, 2014 - link
I had this laptop. I actually had a hell of a time with the intermittent throttling. Believe it or not, it happens fastest and most often with simpler games. Also, I had heavy display corruption with Steam Big Picture mode when using the nvidia gpu.Dell eventually fixed the throttling by replacing the heatsink and fan assembly. It's a tiny piece of hardware too. The corruption in Big Picture mode is still there though.
Silma - Thursday, March 6, 2014 - link
I haven't had any throttling issue since november but then again I'm not using it to play.unni - Thursday, March 6, 2014 - link
If you keep it on a level surface, there doesn't seem to be any throttling. Also, try nVidia inspector and set FPS to 30. That helps as well.Fox5 - Sunday, March 9, 2014 - link
Lol, locking the fps to 30 shouldn't be required. Also, the level surface did nothing for it. I had a legitimately defective model, and replacing the heatsink fixed it.whyso - Thursday, March 6, 2014 - link
Good that they fixed the throttling. I had a 2nd gen model that would idle at 60 degrees and reach over 100 degrees on games like skyrim.Interesting to see that the 750m performs very closely to the 765m in the razer blade.
Also, would it be possible to do some sort of test to see if the PCI-E SSD in the mac lineup actually brings any advantages? Random performance isn't better than anything else out there. Copying files to anything other than a SSD won't be different. The Macbook air reviewed didn't boot up any faster than the 2012 model either. What exactly are the advantages and are they even apparent?
VisionX302 - Thursday, March 6, 2014 - link
I tested the performance of both of these. The Mac was around 1 Gb/s while the Dell was in the 500 Mb/s range. For most real-life activities you wouldn't notice a big difference, but I could a difference in copying files, booting, resuming from sleep, etc.tipoo - Thursday, March 6, 2014 - link
I wonder if it's the same issue, my Studio 15 after some days/hours use would always lock itself at the minimum clock multiplier, had to reset to fix it. I could also fix it through forcing multipliers through Throttlestop, which was also good for me since on Penryn processors they could be undervolted so much that the top clock could use the bottom clocks voltage.tipoo - Thursday, March 13, 2014 - link
And do the larger battery sizes change the size (do they jut out like older models) and how much do they change the weight?superflex - Thursday, March 6, 2014 - link
Jarred,Why make the comparison to the retina MBP in the intro if you dont provide a comparison to the MBP in the charts?
Full retard, baby.