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The Dell Precision 5520 is hobbled by Linux kernel 4.4

The Dell Precision 5520 is hobbled by Linux kernel 4.4


The good

The Precision 5520 is a different class of laptop than the XPS 13, and it shows. The device is physically bigger, looking more like an XPS 15, with Dell’s aluminum and smooth matte-black touches all around.


Of course, most of your time with the PC will be spent looking at the screen, and it doesn’t disappoint. It’s a bright 3840×2160 (4K) touchscreen that keeps things sharp in its 15 diagonal inches of real estate.The screen’s bezel is slim, meaning that more of that expanse is taken up with actual pixels. To that end, Dell has placed the webcam near the hinge, allowing the screen to extend further up top.


The palm-rest area features something many users won’t be accustomed to: an Intel Xeon logo (in place of the more common Core i5 or Core i7 branding), which indicates right away that this machine is all about the cores—of which there are eight—and not necessarily the clocks (although the 2.9GHz clock speed isn’t shabby). In fact, the Precision’s Xeon demolished the Core-grade CPU in the 2015 XPS 13 Developer Edition I used for comparison. The extra cores and higher clocks really paid off in CPU-intensive tasks like kernel compilation and file compression.

The PC also comes with a hefty helping of RAM, to the tune of 32GB. That’s a lot more than the average user will need, but for workstation loads, users will see a big advantage from not having to hit the swap space (virtual memory) on their storage drives.


For connectivity, the laptop comes with three USB ports: one USB-C and two USB 3.0. You also get an HDMI out, an SD card reader, and a Kensington lock. For those who prefer using a mouse, you’ll probably want to go with a Bluetooth option in order to save the two USB 3.0 ports for other stuff.


The bad


There’s a lot to love about this PC’s hardware, for sure. But when it comes to software, the laptop falls flat on its face. There are a number of issues with the Precision 5520 that directly stem from the fact that it ships with Ubuntu 16.04, which in itself is a perfectly fine OS.

First, the Intel Wi-Fi card in the laptop is supported by Linux kernel 4.6 and later, while Ubuntu 16.04 comes with kernal 4.4. That means that in order to get the Wi-Fi to work on the PC, you have to upgrade Ubuntu to 16.10 (or the upcoming 17.04) or install a 4.6 kernel from Ubuntu’s kernel mainline repository.

To update the software and install Phoronix Test Suite for benchmarking, I ended up tethering the laptop to my Android phone to use my home Wi-Fi. I did this after trying an Asus 802.11ac USB dongle (which actually claims Linux compatibility on the box), but the 4.4. kernel didn’t pick up that either.

It was only after this that I realized the laptop comes with an ethernet-to-USB-C dongle. While that would have been far easier to use, it still doesn’t solve the glaring problem that Wi-Fi doesn’t work out of the box. Wireless compatibility has been a running joke among both Linux users and Linux detractors, and this laptop supports the stereotype.

Another issue I noticed was a lack of hardware controls, specifically for screen brightness. For the battery rundown test, I like to keep the screen at about half brightness, or around 200 nits. When I tried pressing the screen brightness keys, there was no response, even while running kernel 4.6. Nor did the power and screen options in Ubuntu feature a slider for brightness. Many of the other hardware control keys, besides the audio controls, also appeared to have no effect.

The benchmarks

Once I ran the tests, the Precision 5520 proved that it has the brawn to back up its exterior beauty. In nearly every test in the Phoronix Test Suite, the Precision stood head and shoulders above the XPS 13.

Thanks to the faster SSD, read performance using a 1MB record size showed an improvement of nearly 18 percent. Write performance was about the same as the XPS 13 for all the storage I/O tests in the IOZone phase of the test suite.

In the Unigine Heaven test, the graphics performance showed nearly 40 percent improvement over the XPS 13. However, that improvement comes with a caveat: The FPS score for the graphics test topped out at 9.07 frames per second, far below any threshold you’d need for a decent gaming experience. Keep in mind though, this is using the default Intel display drivers available in kernel 4.4. Kernel 4.10 includes some improvements for more recent Intel CPUs and graphics.

As for the CPU tasks, the Xeon really smacked around the Core i7 in the XPS 13. For H.264 playback, CPU utilization was around 2.6 percent, compared to the Core i7’s 7.9 percent.

In number-crunching tasks, the Xeon shined as well. When encoding H.264 video, the Precision managed a whopping 202 frames percent, compared to the XPS 13’s 93 frames.

Kernel compilation time also showed an amazing improvement. The XPS 13 took 255 seconds to compile a Linux kernel. The Precision took only 101 seconds. That’s an improvement of over 60 percent, which is nothing to sneer at.

Similarly, the time to encode FLAC audio from a WAV source file took only 5.06 seconds compared to the XPS 13’s 7.65 seconds. That’s and improvement of over 33 percent.

Less impressive was the battery life: While playing an H.264 movie on loop using VLC at full-screen, the Precision lasted a scant 2 hours, 2 minutes. I didn’t expect fabulous battery life from a mobile workstation, but I would have liked to see more than two hours. Of course, given the lack of control over screen brightness and limited power management, the Precision was essentially set up to fail in this area.

I should note here that while I ran the system tests with kernel 4.4, I ran the battery rundown on kernel 4.6. I needed kernel 4.6 in order to ping the network card from another PC as the test was run—as soon as the pings fail to reach the host, the timer stops and returns the time.

The takeaway

Again, a lot of these shortfalls aren’t the fault of Ubuntu 16.04. Dell chose to go with the latest and greatest Intel Wi-Fi components, which perform quite well in a pure hardware sense. Unfortunately, Dell shipped the laptop with a kernel that doesn’t support the hardware.

What does this mean? If you use the laptop as-is out of the box, you don’t get some critical features: Wi-Fi, screen brightness control, advanced ACPI (power) management, hardware control via function keys, or a desktop UI that’s appropriately scaled for the resolution. It’s these shortfalls that cripple otherwise outstanding hardware, and for no other reason than a lack of testing on Dell and Canonical’s part.

Had Dell or Canonical tested Ubuntu 16.04 on the Precision 5520, a fix would have been relatively simple. Dell could have shipped with a later version of Ubuntu, like 16.10, which comes with kernel 4.8 (though this would not have the long-term support of the LTS version). Or Dell could have shipped the laptop with Ubuntu 16.04 but with an appropriate kernel preloaded. The 4.10 kernel added support for Kaby Lake features that the Precision 5520 could have taken advantage of.

Alternatively, Dell could have shipped the laptop with another Linux OS that makes it easier to upgrade the kernel, or has a newer kernel. Both Fedora and openSUSE have stable offerings that could have solved some of these issues.

Indeed, a different Linux distro would have also made more sense given the Precision’s 4K display. While the 4K screen is beautiful, it really doesn’t play nice with Ubuntu’s Unity desktop running the X.org server. Fedora 25, for instance, shipped with Wayland. Wayland plays much nicer with HiDPI displays than X.org, which had to be twisted and forced into compliance in order to feel right.

Instead, it feels like Dell penguin-washed the Precision 5520, which is plain enough to see upon opening the box: The quick-start guide includes instructions for Windows 10, and the underside of the laptop sports a Windows Pro sticker.

Ultimately, a Linux user might get a better experience from the 5520 by wiping it and installing a more recent Linux distribution, which makes it barely any different from a Windows version of the same laptop.

Long story short, this is a fine laptop—and its hardware makes it a far better choice than the Dell XPS 13 for video encoding, compiling code, or other heavy computing tasks. But the OS it comes with is not optimized for the hardware. Hell, it’s not a stretch to say that the OS keeps this PC from being the workstation it’s supposed to be. If anything, this PC is a case study in why PC makers who want to ship desktop Linux should pay attention to what they are doing before they push a product to market. The whole idea of buying a Linux laptop is to avoid these types of troubles, after all. In that respect, the Precision 5520 feels like a step back from the great platform we saw in the 2016 XPS 13.

If you install your own updated Linux distribution on the Precision 5520, it will be a fine portable workstation. But out of the box, the Precision 5520 provides a painful experience that takes a fair amount of technical know-how just to get the basics to work.


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