Is there really a cross-platform battery test that makes sense? I'm investigating, but for now I decided to do video run-down test. It's something everyone can agree is a fair usage scenario.
For what it's worth, Apple rates the 11-inch MacBook Air for 9 hours of browsing and 8 hours of video runtime. The 13-inch model, with the 40 percent larger battery, gets you to 12 hours of browsing, 12 hours of movies.
Dell rates the QHD+ version of the XPS 13 for 11 hours of browsing and 8 hours of HD video playback. The 1080p version of the XPS 13 takes it to 15 hours of browsing and just under 13 hours of video.
Each company uses its own battery methodology that can't be directly compared. Even the "browsing" tasks are different: Apple uses iTunes to play a 720p video, while Dell uses Microsoft's standardized Windows Assessment & Deployment Kit, which uses an H.264 file to gauge battery life in Windows-based devices. With two different video files and two different video players, it's like comparing oranges and bricks.
How I tested
To make it as even as possible, so I grabbed VLC 2.1.5 for OS X and Windows and used the 1080p Big Buck Bunny .OGG file PCWorld has. You should know that using VLC on Windows hardly favors the platform--in fact, it's downright mediocre in optimization. Tim Schiesser over at TechSpot has done some great testing on this front, and other individuals have validated his findings. For my tests, I disabled hardware acceleration in VLC on both platforms, as I saw screen corruption when I enabled it under OS X.
I disabled variable screen brightness on both platforms and set the brightness to as close to 190 nits as I could on all three laptops. The QHD+ was actually putting out closer to 200 nits. I used our Minolta Photometer to measure the laptops' display brightness at dead center.
If you're setting the laptops based on the percentage of slider controls, you should know that doesn't mean much. Setting the the MacBook Air 11 to 50-percent brightness is about 64 nits, while the same middle of the slider setting on the XPS 13 QHD+ is 185 nits. That's a huge difference.
So as not to annoy my officemates, I ran our tests with volume muted, which isn't realistic, but at least the audio was not a factor. Since I wrote my original review, I also was able to obtain the 1080p version of the XPS 13 that has 4GB of DDR3L/1600. My results are in minutes and were manually recorded by having all three laptops sitting on my desk and noting the time when the screens finally went to black. WiFi was hot on all three, but the connected router went nowhere, so there was no chance of their downloading updates in the background.
Sign up for CIO Asia eNewsletters.