Verdict

Pros

• Very slim and light
• Strong usability
• Well-designed screen

Cons

• Pricey
• Weak audio

What is the Asus ZenBook 13 UX331U?

‘The thinnest laptop on the planet’ is how Asus describes the ZenBook 13 UX331U, a machine that’s just 13.9mm thick at its chunkiest point. And while that boast isn’t quite accurate – Acer’s Swift 7 is a shade under 9mm, for one example – there’s no denying that this super-slender machine is well designed for life on the road.

Despite that slim finish, the ZenBook still packs some decent specs and a Full HD 13-inch display. So is it well suited to mobile professionals and anyone else who wants to stay productive on the move?

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Asus ZenBook 13 UX331U – Design and build

If portability is high on your list of priorities, then the ZenBook 13 will be right up your street. This 1.12kg laptop almost reaches the realms of the Ultrabook with its super-light chassis, which is also pleasingly slender. It’s comparable to the likes of Huawei’s MateBook X Pro, even if the screen bezels aren’t quite as ridiculously thin.

The glossy lid offers a very different finish to the usual brushed metal constructions, with a dark colour to help hide scuffs and greasy prints. With only very slight pressure, the lid does bend by quite a worrying amount. Thankfully, the display doesn’t warp as a result, which is at least partly reassuring.

Open up the ZenBook and you’re presented with a smart matte chassis that feels far more sturdy. The edges are lined with a generous number of ports, considering the slim finish. You get two USB 3.0 ports and a dinky Type-C USB 3.1 port as well. In addition, there’s HDMI to connect to displays and projectors, plus a microSD card reader for transferring files.

Asus has also added a fingerprint sensor, located on the palm rest to the right of the touchpad. This is a handy alternative to password security, allowing you to swiftly unlock the laptop. It’s a perfectly responsive scanner and I like the shiny trim that makes it easy to locate, even in low light.

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Asus ZenBook 13 UX331U – Keyboard and touchpad

That commendable design continues with the ZenBook’s excellent keyboard and touchpad. Asus rarely disappoints when it comes to usability, and I immediately got to grips with the chiclet keyboard, reaching peak touch-typing speeds in no time at all.

Travel distance takes a bit of a hit thanks to the slender build, but this isn’t a deal-breaker. Those keys still depress into the chassis when struck, so you know for sure that you’ve scored a hit when your fingers are flying. Despite the compact 13-inch form factor, the keys are also well spaced. A mis-hit was rare, even when using the cursor keys (which are squashed into a single row as usual).

Burners of that midnight oil can work all through the night as the keyboard is fully backlit. You have three brightness settings to choose from, or you can knock it off entirely to save your battery.

Laptop touchpads can be a full-on source of frustration and rage, but the UX331U’s pad is absolutely fine. Occasionally, a click of the built-in buttons will send your cursor drunkenly staggering across the screen, which is a pretty common complaint. However, the touchpad is also perfectly responsive to your finger shuffles. Multi-touch gesturing works beautifully, and you can simply tap the surface to perform a left-click when needed.

Asus ZenBook 13 UX331U – Screen

Another of this Zenbook’s strengths is the visuals. That compact 13.3-inch display boasts Full HD image reproduction so photos, movies and everything else will appear pleasingly crisp. You practically have to mush your face up against the panel to spot any individual pixels.

Viewing angles are nice and wide, so you’ll have no trouble watching a movie with one or two mates. No need to cram your heads together awkwardly. Visibility is no problem on sunny days, either. On maximum brightness, the screen gives out quite a lot of power, while the anti-glare coating also helps.

You can also expect reasonably realistic colour reproduction. An impressive 95% of the sRGB gamut is covered by the ZenBook 13, although this dips to 73% for Adobe RGB users.

Asus ZenBook 13 UX331U – Audio

My expectations are rather low when it comes to laptop audio, especially from super-compact machines such as this ZenBook. After spending plenty of time consuming music and movies with the UX331U, my opinion hasn’t changed.

The biggest problem is that those dual speakers are housed on the underside of the device, so any output is muffled by the desk or your lap – or whatever the device is resting on. However, even if you lift the laptop, the sound is still weak. In a quiet environment, you’ll struggle to make out conversations in flicks and TV shows. Headphones are a must.

Asus ZenBook 13 UX331U – Performance

Although our review model was the more basic Core i5-8250U version, you can also grab the UX331U with an upgraded Core i7-8550U chipset. In either case, 8GB of RAM sits alongside to keep things moving smoothly.

As a result, I had no trouble multi-tasking on the move. That Core i5 platform handled office software without breaking a sweat, all while streaming music or video at the same time.

Of course, since this laptop’s priorities focus on size and weight, you won’t find a dedicated graphics card shoved inside of that slender chassis. Rather, Asus has stuck with Intel’s integrated graphics solution. That means only older or less demanding games will play with a respectable frame rate, while intensive tasks such as 4K video editing are a struggle.

At this price point it’s perfectly possible to find laptops with dedicated graphics. However, you’ll have to sacrifice some of that lightweight design.

For instance, the Lenovo IdeaPad 520s boasts an Nvidia GTX GPU in some configurations, but it also weighs in at 1.7kg and is significantly chunkier. The only way around this problem is to bump up your budget for Huawei’s MateBook X Pro, for example.

In the standard Trusted Reviews benchmarking tests, the ZenBook 13 scored the following.

PCMark 8: 3211

Geekbench single core: 4137

Geekbench multi-core: 14137

The 256GB SSD also performs as expected, with read speeds of 529.4MB/sec and write speeds of 446.9MB/sec.

Asus Zenbook 13 UX331U – Battery life

Slender laptops commonly suffer when it comes to battery life. Manufacturers often have to make sacrifices in this area to keep the device slim and light, although the use of more energy-efficient components usually helps.

The ZenBook 13 UX331U won’t make it through a full working day on a single charge, but it isn’t far off. I typically managed around five to six hours of mixed use before the battery was drained. That mostly involved working in-browser while streaming music, with occasional bouts of Netflix, photo editing or app play thrown in.

In the standard Trusted Reviews battery test, this machine lasted a sniff under six hours. That involves running a non-stop loop of video playback and web browsing until the laptop dies.

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Why buy the Asus ZenBook 13 UX331U?

If you’re after a capable professional laptop to take on the road every day, the ZenBook 13 certainly ticks most of the necessary boxes. Not many laptops can boast being this thin and lightweight, while still packing respectable specs.

That said, the likes of Acer’s Swift 5 offers a similar setup to this Asus machine for around £200 less. So if you’re willing to shop around a bit, you’ll find comparable experiences for a price that won’t empty your wallet quite so quick.

Verdict

The Asus ZenBook 13 is impressively slim and light, making it well suited to mobile professionals.

Trusted Score