Although Linux-compatible hardware is not nearly as serious an issue nowadays as it was, it's still something of a minefield. This applies, in particular, to peripherals, such as multifunction printers, but also to other hardware like notebooks. The KDE Slimbook is a notable exception [1], as it already comes with a preinstalled and configured Linux operating system.

Compatibility is not only an issue for end users, but also for software developers, who have only a limited selection of hardware available to test their software. The colleague with whom you're working on a project probably does not own an identical notebook with compatible hardware. The KDE developers have now come up with a solution to this.

The Slimbook, like Dell's XPS series, is primarily aimed at developers and Linux fans. In designing the 13.3-inch small Ultrabook, which bears a striking resemblance to the MacBook Air, KDE Project developers wanted hardware that would work seamlessly with the operating system, Plasma environment, KDE applications, and KDE frameworks.

One for all?

The KDE Slimbook not only provides the KDE developers with a comparable work base, but also ensures that device owners have the same hardware compatibility issues they do when using software. Last year Jonathan Riddell, former lead KDE developer, took the first steps towards establishing a common base.

With the release of the project KDE neon, developers created a reference operating system, which made two out of three potential error sources easier to compare. The operating system and desktop environment were already in place, only the hardware remained a great unknown. The KDE Slimbook is designed to provide a solution to this problem and to serve as a reference platform for this third component (Figure 1).

Figure 1: The Fairphone OS has no superfluous applications.

Old Faithful

The KDE Project provided us with one of their first Slimbooks for a week. We received the more powerful version running an Intel i7-6500U processor with a clock rate of 2.5GHz. Our testing machine had 8GB of DDR3 RAM (the standard is 4GB) at 1600Mhz. The basic model is equipped with an Intel i5-6200U CPU with a clock rate of 2.3GHz. The prices for both models without any hardware upgrades are EUR729 (~$797) and EUR849 (~$928) respectively. Our test model was worth EUR909 (~$994). The manufacturer offers a two-year warranty.

Both processsor types are dual core, which use hyperthreading based on the Intel HD-520 integrated graphics unit. The economical ultra low voltage (ULV) processors offer a thermal design power (TDP) of 12W or 15W. The Intel platform used is called Skylake, which has now been succeeded by Kaby Lake.

The Slimbook's RAM can be upgraded up to 16GB (Figure 2).

Figure 2: The command-line program Inxi reveals what is in the Slimbook.

Under the Hood

The Slimbook has an aluminum case measuring 33x22x1.8cm and weighs 1.36kg. The backlit keyboard offers a variety of English or European layouts. Data is stored on a 120GB mSATA-SSD, which can be upgraded to a 250GB or 500GB model for an extra charge.

The matte 13.3-inch IPS LED display will display full HD video (1920x1080), providing a pixel density of 166 PPI. Screen brightness is a respectable 355 cd/m2. You can connect the Slimbook to the outside world via WLAN with the Intel Dual Band Wireless-AC 3160. Alternatively, the Intel Dual Band 726 5N or Wireless-AC 7265 are available, which also provide Bluetooth 4.0.

The Slimbook has two USB 3.0 ports, a mini HDMI port, and a slot for SD and MMC cards. The hardware specification also includes a front-facing 1MP webcam. The lithium-ion battery has a nominal power of 6800mAH, but the manufacturer hasn't said how long this should last. Some online reports claim the device has a rather unrealistic run time of up to 12 hours. In our tests, the battery lasted an average of seven hours.

Elegant

After unboxing and handling the Slimbook for the first time, it's clear the device fits snugly into your hands and is nothing less than elegant. The aluminum lid is decorated with the combined logo of Slimbook and KDE (Figure 3). On closer inspection, it turns out the casing is quite familiar, sharing its basic structure with last year's Tuxedo InfinityBook and the Schenker S306.

Figure 3: There's a combined KDE/Slimbook logo on the center of the lid.

Along with our test equipment, beside the notebook and the charging cable itself, we received a USB Ralink MT7601U wireless dongle, which can provide better throughput for older routers than the preinstalled Intel Dual Band Wireless-AC 3160 WLAN chip.

After booting the KDE Slimbook, the first step is to complete the dialog-driven OEM installation. Setup includes creating a user account and setting up WiFi amongst other things. Despite being told we could use wireless right away, we found WLAN only worked after rebooting the Slimbook. However, it then worked properly via the network manager over further restarts, as well as when waking from sleep.

¿Habla Español?

The Slimbook offers new users a kind of setup assistant called Slimbook Essentials, but at the time of testing, it only worked in Spanish. Non-Spanish speakers can use this with some help from Google Translate (Figure 4). The developers, however, assured us that there will be an English version. The app is also available in the Launchpad as a PPA [2].

Figure 4: The setup assistant Slimbook Essentials was only available in Spanish on our test Ultrabook.

The Aplicaciones tab is still easy to use even without a translator. It allows you to install programs like Google Chrome, Gimp, VLC, or Wine, as well as unblocking services like SSH or NFS. The individual task progress is shown in a console to the right of the window.

The tab Ajustes (Adjustments) contains switches for system settings, such as an optimization line for the SSD in the / etc / fstab file, Contrib- , and Non-Free Options in sources.list . You can also configure Bluetooth or WiFi or update the entire system. Utilidades contains various system information and tests, as well as the ability to remove old kernels.

Convenient Keyboards

In order to get the correct layout, check the system settings under Input Devices | Keyboard | assignments , and then set the keyboard accordingly.

The keyboard has 101 keys. Our pre-production model was missing the characters <, >, and |. On the Slimbook website, the keyboard shown also seemed to be missing the pipe sign. The overall typing experience is pleasantly precise and not spongy as can be the case for notebook keyboards. For working in darker environments, the backlight can be set to various intensities via Fn+F5.

An Adequate SSD

The already somewhat mature mSata SSD Kingston mS200 with 120GB capacity has a reading speed of just under 400MByps, reaching about 200MByps when writing. More modern SSDs are faster. Nevertheless, the bundled drive is compatible with the system and should be sufficient for most users. It's also several times faster than conventional mechanical hard disks. If you need a larger SSD, however, it may be better to order the standard 120GB drive and replace it with a better one yourself.

Upgrading components such as RAM, SSD, or the WLAN module is very user-friendly. You just need to loosen the 12 screws on the back cover to reach them.

Low Noise

The strategically placed gaps in the aluminum housing make for good heat dissipation and will likely keep the Slimbook ticking over nicely. This in turn makes itself felt in a pleasantly quiet working environment. During testing, we transcoded a video using the editor Handbrake , which loaded the CPU on all four cores to over 90 percent. Only when we placed our ears very close to the casing did we hear a low noise. Even using the stress tester cpuburn , which constantly serves a 100% load on all cores, the fan remained inaudible at a distance of 30cm.

In order to get a comparable test of the main components, we installed the Phoronix Test Suite (PTS) [3] from the vendor site as the Ubuntu version was completely out of date. We used the Universe suite, which offers the most extensive tests [4].

Conclusion

Our testing week with the KDE Slimbook was fun. There were many good points, but also a few bad ones. Thanks to the aluminum case, this 1.36kg, very portable Slimbook is a joy to handle, both cool and stylish. The area on the left and right of the touchpad warms up only slightly, even for very demanding tasks.

The Slimbook worked smoothly without any issue. It certainly seems suited for developers, who frequently need to collaborate on compiling compatible software. For gamers, the integrated graphics unit might be sufficient, but not for hardcore players.

The matte screen and the fact the fans are barely audible, even for heavy tasks, make the Slimbook even more agreeable.

The decision to use Intel's Skylake instead of the latest generation Kaby Lake plays a key role in terms of pricing, which is comparatively moderate. However, the RAM should be DDR4-2133 instead of DDR3-1600, as the motherboard supports this.

Our criticism is otherwise limited to two things. Firstly, the Spanish-only setup app Slimbook Essentials was not yet available in English when the device went on sale in April. Secondly, the keyboard has not yet been optimally designed. However, this should be remedied in devices that are shipped to end users.