Asus ZenBook UX21 and UX31 hands-on first look review

Gorgeous and sleek rival to the Apple MacBook Air
Photo of Asus ZenBook UX21 and UX31 hands-on first look
£849 for UX21; £999 for UX31

With the launch of Asus’ new ZenBook ‘ultrabook’ laptop range – currently comprising the ZenBook 11.6in UX21 and 13.3in UX31, equipped Intel Core i5 and Core i7 processors, respectively – Apple’s MacBook Air finally has a fight on its hands.

Slim and light
Heralded by Asus as the “perfect blend of elegance and power”, we were pretty hard-pressed to disagree when we got our hands on one of the slimline beauties at the press launch. Featuring a passive cooling system slimmer than that of the MacBook Air – if only by 1mm – the two ZenBook models measure a positively sylphlike 3mm thick at the front, graduating to 11mm at the rear. Weights for the two models are just 1.1kg and 1.3kg.

Asus ZenBook

Given those dimensions, we were pleasantly surprised by how sturdy both ZenBook models felt, with no flex in the screen thanks to a solid, brushed metal chassis, and a stiff hinge with a definite action that keeps the two halves of the clamshell design closed without the need for a catch.

Asus ZenBook

Core specification and performance
In terms of performance, though, the ZenBooks are pitched as heavyweights. The smaller 11.6in UX21 boasts an Intel Core i5-2467M, clocked at 1.6GHz, while the 13.3in UX31 is powered by a 1.8GHz Intel Core i7-2677M. That’s backed by 4GB of DDR RAM in both models.

The result is a nippy, responsive machine that handles multimedia, as well as standard tasks using the installed 64-bit Windows OS, without breaking a sweat.

Asus claims the ZenBook’s graphics are 34 per cent more powerful than an unnamed direct competitor – that’s the MacBook Air, to you and me – but hardcore gamers will nevertheless be disappointed – provided by an integrated Intel graphics chipset, the latest shooters are a definite no-no.

Asus ZenBook

Both models offer high-resolution displays (1440×900 for the UX21; 1600×900 for the UX31), with even illumination across the screen and bold, bright colours. Audio is well catered for, with Asus’ SonicMaster technology – an “optimised fusion of hardware and software” involving specially tweaked audio codecs – gaining the seal of approval from Danish audio experts Bang & Olufsen, whose logo is beneath the ZenBook’s comfortable and well-spaced keyboard.

Sound was decent enough, with the built-in speakers cutting through the din at a noisy press event without any sign of distortion. As you’d expect, though, they’re pretty thin on bass.

Asus ZenBook

Instant on
What really sets the ZenBook apart from the PC crowd, though, is its claimed ‘instant-on’ time of just two seconds to boot from sleep – a claim that was borne out in our testing. This comes courtesy of the laptop’s 128GB SSD, which takes advantage of the latest SATA 3 hard disk interface to retrieve data at a theoretical maximum transfer speed of 6GB/s.

Usefully, we were told in spite of the ZenBook’s extremely svelte dimensions, the SSD is a standard 1.8in part – as, indeed, is the both 4GB SODIMM memory modul, meaning that both components could be upgraded in time to something even bigger and better.

While respective battery life under normal use of 5 hours for the UX21 and 7 hours for the UX31 may not seem particularly impressive to those used to going days between charges on a tablet, remember that these machines are powered by a fully-fledged PC processor. Standby time is particularly impressive at two weeks.

Asus also says its ‘instant-on’ time of two seconds hold true throughout the standby time – something that’s not true of many rivals, which park data onto their storage drive after a time in an effort to reduce battery drain. To avoid data loss, the ZenBook automatically saves the contents of the memory onto a specially designed 4GB partition whenever the battery’s charge drops below five per cent.

Connections and features
Connections are reasonably well provided for, in spite of the ZenBook’s slender dimensions, with one USB 2.0 port, one USB 3.0, a micro-HDMI and mini-VGA for hooking up external monitors, plus an audio jack. The larger UX31 model supplements those with an SD card reader. Wireless 802.11b/g/n networking is built in, as well as the latest Bluetooth 4.0 standard. Obviously, given the laptops’ dimensions, there’s no room for an optical drive of any kind in either model.

Asus ZenBook

Company: Asus


  • Utterly gorgeous; plenty of processing power.
  • Some battery life has been sacrificed to keep the dimensions down.


Lush to look at, the ZenBook just oozes class - which is why the price, while still placing these models into the premium bracket, came as a bit of a surprise. The 11.6in UX21 costs £849, while the 13.3in UX31 sells for £999 - coincidentally, the prices of Apple's two entry-level MacBook Air models. But spec for spec, the ZenBooks outclass their Apple competition by some margin, doubling the capacity of the SSD to 128GB and upping the processor in the £999 model to an Intel Core i7 against the Air's i5. Expensive they may be, but to those seeking the ultimate in PC style we reckon the new Asus ZenBooks are worth every penny. Check back on ITReviews soon, when we put the ZenBooks through their paces in a full lab-tested review.