Dell XPS 15z: Sincerely Flattering

1080p Upgrade FTW

We loved the AU Optronics B156HW1 panel in the XPS 15, and we’ve seen several versions of that panel in the Clevo P150/P151 and W150HR chassis. Out of all of those displays, my favorite by far is the B156HW01 v4 matte panel we tested recently in the W150HR. The XPS 15z brings a new AU Optronics into the picture, however: the B156HW03. The good news is that this is still a decent 1080p LCD, with >500:1 contrast ratio. The bad news is that it’s not as good as most of the B156HW01 panels that we’ve tested (outside of the B156HW01 v5, used in the MSI GT680R). Color accuracy after calibration is particularly bad, and try as I might I couldn’t improve the score. That’s unfortunate, but outside of professional imaging/video work the color accuracy is “good enough” that most users won’t be bothered. Here’s how the new panel compares to other laptops.

While the XPS 15 sports a slightly higher contrast ratio, I’d actually take the higher maximum luminance offered by the 15z panel. Ideally, I’d still like to see >400 nits maximum brightness (you know, like the MacBook Pro offers?), but 300 nits is better than average. Color gamut is only 56% AdobeRGB 1998, which isn’t exceptional but is at least a step up from the 40-50% panels found in cheaper laptops. The Delta E score on the other hand is actually the worst post-calibration result I’ve ever measured. Yikes. Some of the colors in the test are still coming in at >10, which is what we typically see without calibration. I tried 1.8 gamma, 2.2 gamma, and several white points, all to no avail. It’s not the end of the world—most people don’t even have a colorimeter in the first place—but it is somewhat perplexing. Overall, I’d give the panel a solid B, where the B156HW01 v1/v4/v5/v6 rate A-/A/C-/A- respectively (and the Dell panel is another A-, though I’m not sure if it’s v6 or something else). Viewing angles are also good, at least for TN panels:

Heat and Noise Levels

One area where we have to offer a word of caution is in regards to temperatures. We’ve seen at least one laptop throttle CPU speeds when the cores hit 85C, and under a sustained load the XPS 15z CPU runs a toasty 90-95C. Of course, the 85C throttling is on the Acer TimelineX 3830TG, and it’s a BIOS setting rather than a CPU limit—Intel specs all of the Sandy Bridge CPUs for up to 100C operation. Even so, 95C is more than we’d like, and the culprit is easy to find. Simple physics dictates that a thinner chassis makes it harder to get airflow, and stuffing a high performance CPU into such a chassis is a recipe for heat. It happens with the MacBook Pro, and it happens on the XPS 15z. The difference is that Apple uses a fan that can spin faster (and generate more noise), while the 15z runs slightly hotter but doesn’t get quite as loud. At idle, noise from 18” measured 31.6dB on my SPL meter (in a 30dB environment), while load noise—from gaming or running a CPU-intensive task like Cinebench—maxes out the fan at 42.2dB.

The 15z chassis could also benefit from better air intake locations; it sits flat and close to the ground, and if you place it on a carpet or a lap and run a game, you’ll find it gets uncomfortably warm. Prop the back of the laptop up so that the bottom intake can get fresh air and maximum CPU temperatures drop around 8C (though the fan noise remains the same).