MobileMark 2014 is unlike most mobile benchmarks in that it measures only the response time and actually allows a laptop to stop and pause. You don't, for example, type for seven hours straight in Word. You type, pause, use your phone for a few minutes and then go back to typing. Then you task-switch to email. MobileMark actually lets the laptop's screen dim or blank out before resuming a task. MobileMark 2012 remains the industry standard among OEMs for testing, so we're actually a little ahead of the curve now.
It's also worth mentioning that the battery in the XPS 13 is rated at 52WHr, which is actually a reduction from the previous XPS 13, yet it offers better battery life.
Our MobileMark 14 run in Office-drone tasks puts the battery life at 10 hours for our configuration. The XPS 13 with the 1920x1080 screen without touch actually ups the battery life another four hours, to nearly 15 hours of use. If you're looking to go off-grid even longer, add Dell's PowerCompanion battery brick so you can charge the laptop much as you would your phone.
As with the badly placed camera, Dell made one other dubious choice with the XPS 13: the keyboard design. Dell crams the important keys (function keys don't count to me) in a space about 10.5 inches wide and 3.53 inches deep. Travel is rated at 1.3mm.
The Lenovo X1 Carbon's four rows fit into a spacious 11.3-by-3.6-inch box. Even the MacBook Air 11, which is physically a bit smaller than the XPS 13, gives the keyboard 10.75 by 3.5 inches.
To see whether the smaller keyboard would impact my typing, I took an online test on the X1 Carbon and the XPS 13. I typed at 72 wpm on the X1 Carbon and 70 wpm on the XPS 13, producing six errors both times. On a full-sized Corsair K60 mechanical keyboard, I hit 88 wpm. The keyboard on the XPS 13 is tolerable, but definitely a compromise.
The trackpad appears to be made by Synaptics and I had no complaints. Despite the cramped quarters, my palms didn't cause cursor jump, but there was also no way to adjust palm rejection on the XPS 13.
One final spec to mention in the XPS 13 vs. MacBook Air battle is the SSD. The XPS 13 uses an M.2 SSD, but it conforms to the SATA portion of M.2 and thus isn't a true PCIe drive. I saw sequential reads and writes in the 450MB/s range. That's decent, but PCIe-based storage devices like in the MacBook Air can reach close to 800MB/s.
Dell said it has plans to release a PCIe-based SSD for the XPS 13 soon. Before the Apple crew stars to crow though, I should mention the M.2-shaped devices in the Haswell-based MacBook Airs aren't actually M.2--they're a custom, proprietary design, so you can't just upgrade using off-the-shelf parts.
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