Asus ZenBook Flip S (UX370UA) review: The slimmest 2-in-1 laptop in the world

Building on last year’s ZenBook Flip UX360CA, the ZenBook Flip S is Asus’ latest creation – a truly gorgeous machine to behold. Asus’ main selling point for the 13.3in laptop is its ludicrously thin design but, despite the fact that it’s only 10.9mm thick (making it the slimmest 2-in-1 on the market), Asus has somehow managed to squeeze in a 360-degree hinge and full-fat Kaby Lake Core i5 U-series processors as well. Could this be the ultimate 2-in-1 laptop?

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Asus ZenBook Flip S review: What you need to know

In short, it all depends on what you need from an ultra-portable laptop. Granted, the Asus ZenBook Flip S is an excellent device but you can save yourself £450 and get the impressive Asus ZenBook 3 instead. The latter won’t fold over but is still an ultra-thin, stylish laptop that features all the key ingredients you’d want from a Windows machine.

Still, if you are looking to get a 2-in-1 device, the Asus ZenBook Flip S won’t disappoint. It’s a joy to type on, has a premium look, a full-fat Core i5 processor and a convenient fingerprint sensor for added convenience.

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Asus ZenBook Flip S review: Price and competition

The Asus ZenBook Flip S, also known as the UX370UA, costs around £1,260 from Amazon. You’ll find it at John Lewis for a similar price and at Currys for a little more. It comes with a Core i5-7200U, 8GB of RAM, a super speedy 512GB PCIe SSD, a Full HD 13.3in display and a stylus pen.

It isn’t short of competitors, the strongest from Asus’ own product line. At £810, the Asus ZenBook 3 is an incredible laptop. It has the same specifications as the ZenBook Flip S, but a smaller 12.5in Full HD display. So, where’s the catch? There’s no touchscreen, the display doesn’t flip over, nor does it come with a stylus.

If that’s what you want, the HP Spectre x2 (2017) is closer contender. At £1,500 from HP’s website, you’ll get an Intel Core i7-7560U processor, 8GB of RAM, a 512GB SSD and a lush 3,000 x 2,000 12.3in display.

Then, there’s the Microsoft Surface Pro, the equivalent specification of which costs £1,249 and comes a Core i5 but half the storage and doesn’t include the keyboard or stylus. You could always get the Surface Pro 4. At £1,130 it ships with the older generation Core i5-6300U, 8GB of RAM, a 256GB SSD and a stylus. Add the £100 Type Cover to the package and the total is £30 cheaper than the Asus ZenBook Flip S.

Others include the Acer Spin 7 at £1,200, which has an Intel Core i7-7Y75, 8GB of RAM, a 256GB SSD and a Full HD 14in display. The £1,429 Dell XPS 13 2-in-1, meanwhile, is practically identical to the Acer, apart from its slightly smaller 13in screen. There’s also the £1,378 HP EliteBook x360 G2, which comes with a Core i5-7200U processor and 13.3in display instead.

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Asus ZenBook Flip S review: Design and build quality

Just like the Asus ZenBook 3, the ZenBook Flip S’s all-metal 6013 aluminum alloy unibody is gorgeous. According to Asus, it’s built from “automotive and aerospace” grade materials and is 50% stronger than a standard alloy compound. At 10.9mm thick, it’s the world’s thinnest convertible laptop.

Its sumptuous Royal Blue colour and diamond-cut golden edges provide an elegant look and everywhere you look, there are little touches of class. Even the backlit keyboard has a subtle golden hue, but Asus hasn’t neglected build quality or features. The laptop’s hinge is well made and allows you transform the laptop into a tablet effortlessly and on the right-hand edge, unusually, is a slim fingerprint reader, which can be used to unlock the Asus ZenBook Flip S with blistering speed.

Connectivity is limited, as you’d expect from a laptop this thin. It has two USB 3.1 Gen 1 Type-C ports, one on each side and both of these support power, data and display (up to 4K UHD). There’s a 3.5mm headphone/mic combo jack to the left, and a volume rocker and power button on the right-hand side next to the fingerprint reader. For wireless connectivity, there’s dual-band 802.11ac Wi-Fi and Bluetooth 4.1.

Underneath the laptop, you’ll find two Harmon Kardon-branded speakers. Considering how slim the laptop is, these are incredibly good. These produce an impressive full-bodied sound that make watching content on the laptop more engaging.

Through the AudioWizard app by icePower, you can quickly toggle between sound profiles, or set up your own through the “Advanced” section.

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Asus ZenBook Flip S review: Keyboard, trackpad and pen

Asus has really nailed the keyboard, trackpad, and pen, too. First, the keyboard, which thanks despite only 1mm of key travel is a joy to type on. It’s quiet, too, which all comes together to give it a 2017 MacBook-feel.

The touchpad is awesome, too, tracking movement and pinch-to-zoom gestures flawlessly. I didn’t experience any issue in left- or right-clicking either despite the fact the laptop doesn’t have discrete buttons.

The bundled Asus Pen is a great addition to the laptop, especially when used with Windows Ink. It is able to detect 1,024 levels of pressure and you only need to apply 10g of pressure on the pen nib to the screen to get it to start drawing. It isn’t quite as good as the newest Microsoft Surface Pen, which has 4,096 levels of pressure sensitivity and tilt detection, but it feels just as sensitive for the most part.

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Asus ZenBook Flip S review: Display

The ZenBook Flip S has a 13.3in Full HD (1,920 x 1,080) multitouch display that uses an IPS panel. Putting it through our colorimeter, the screen achieves 84.6% sRGB gamut coverage, which is lower than the HP Spectre x2’s 91.7% and Surface Pro 4’s 97.5%. This means colours are slightly less vibrant but not by much. Colour accuracy isn’t bad either, but again, it’s outpaced by its main rivals here.

Contrast is good too, with a measured ratio of 1,321:1 and a black level of 0.2cd/m2 at maximum brightness.

The screen’s weakness is its ability to display a bright image. At 326cd/m2 peak brightness, the Asus lags behind its competitors. The HP Spectre x2 and Microsoft Surface Pro 2017, for instance, measures 488cd/m2 and 437cd/m2 respectively in the same test. Using the ZenBook Flip S will, therefore, be a little tricky in bright rooms with a lot of sunlight.

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Asus ZenBook Flip S review: Performance

Inside the slender laptop there’s a 2.5GHz Intel Core i5-7200U, 8GB of 2,133MHz LPDDR3 RAM and a super speedy 512GB PCIe 3.0 M.2 SSD, which should be plenty for most applications.

Multitasking is a breeze, intensive applications are easy to churn through, and for everyday tasks, the ZenBook Flip S provides everything you’ll ever need.

In the Expert Reviews benchmarks, the Asus ZenBook Flip S holds its own versus the Zenbook 3 (Intel Core i5-7200U) but it’s outpaced by the Core i7-7660U Surface Pro we tested earlier this year.

^ Asus ZenBook Flip S review: Benchmark table

In the cross-platform Geekbench 4 benchmark, the Asus shows its prowess with an impressive score of 3,604 in its single-core and 7,246 in its multi-core benchmark. Similar to the Surface Pro 4 with an Intel Core i5-6300U that manages 3,634 and 7,046 respectively.

^ Asus ZenBook Flip S review: Geekbench 4

What was particularly impressive about the Flip S, though, is how cool and quiet it remained throughout. It isn’t fanless, but I was barely able to hear it over the hum of the office air-conditioning and the CPU peaked at a maximum temperature of only 71°C. That’s vastly impressive for a laptop of its thickness. By comparison, the HP Spectre x2 reached a peak of 96°C and got distractingly loud as we ran our tests, running the risk of throttling and a subsequent drop off in performance.

Its Intel HD Graphics 620 GPU can handle games, too. Put through the intensive GFXBench benchmark, the Asus achieved average frame rates of 53fps and 26fps in the Manhattan 3 and Car Chase tests. Against some of its competitors, such as the HP Spectre x2 (42.6fps), Acer Spin 7 (36.3fps) and HP EliteBook x360 G2 (45.7fps), the slender Asus laptop holds its own at Full HD 1080p. So, if you want to play some Counter-Strike: Global Offensive on the lowest settings, you should be able to do so.

^ Asus ZenBook Flip S review: SSD performance

For storage, Asus has put in a 512GB PCIe 3.0 M.2 SSD. This absolutely flew through our SSD benchmarks, with a sequential read and write speeds of 1,780MB/sec and 613MB/sec respectively.

^ Asus ZenBook Flip S review: Battery life

Its battery life is rather mediocre, however, lasting 5hrs 27mins in the Expert Reviews video test. In short, it will struggle to get you through you a full day of moderate use without needing a top-up charge along the way.

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Asus ZenBook Flip S review: Verdict

The Asus ZenBook Flip S is a fantastic 2-in-1: it’s well-engineered, fast, packed with useful features and at only 10.9mm thick with a beautiful colour scheme, a fingerprint sensor and a blisteringly quick Core-i5 processor, there aren’t many competitors that come close.

In fact, if a 2-in-1 convertible is what you want then this is currently the best you can buy. As ever, though, I’d urge you to consider before splashing out whether you actually need the 2-in-1 features. Because if you can do without, Asus’ own Zenbook 3 is a much better value ultraportable, costing £450 less.