Asus ZenBook UX305C review

Asus UX305C and its striking resemblance to the MacBook Air...

Asus UX305C still bears a striking resemblance to the Apple MacBook Air

Asus knows a winning formula when it copies it, hence the ongoing development of its tribute to the MacBook Air, the ZenBook. The latest version to roll up in early 2016 is an update to the UX305F model that launched around this time last year. Confusingly, this newer version drops back a few letter suffices, and is labelled the UX305C. Or optionally UX305CA, just to muddy the waters further.

Like the aforementioned ’305F ZenBook, the UX305C is powered by a special low-power Intel processor which tries to provide some of the performance of the company’s all-conquering Core series chips, but with power consumption closer to the woefully underpowered Intel Atom line. So in this laptop we find the Intel Core m3-6Y30, a dual-core chip nominally clocked at 900 MHz and with potential to spread its little wings to 2.2 GHz for short bursts at least.

Make that ‘very short bursts’, since the raison d’être of these Core m processors is operation so cool they don’t need active cooling. The chip inside this laptop has an advertised thermal design power (TDP) of just 4.5 W – the Intel Core i5 in the MacBook Air is three times higher at 15 W. So no annoying fans required.

(Cooling fans in many Windows laptops can be particularly annoying as they hunt up and down for thermal equilibrium, even with the machine just left idle on the desk.)

But without the means to quickly dissipate heat when demand spikes, the processor instead steadily slows down from first its peak turbo speed, back to nominal speed, then underclocking if necessary to reduce heat until the load or temperature stabilises.

Storage is all solid-state too, leaving no moving parts in this laptop. The drawback as ever is limited performance available when required to get the work done, although in the case of that first Core m ZenBook, it at least didn’t feel especially slow in general duties around the OS interface. Benchmark results did reveal it to be slower than an iPad Air in CPU speed however.


Focusing first on the hardware, the ZenBook UX305C follows the same MacBook Air template as before, with an all-aluminium chassis that in profile tapers down to a sharp edge toward the front. Unlike Apple’s single choice of natural aluminium finish, the ZenBook is available in dark grey (Obsidian Stone), natural silver (Ceramic White) or light bronze (Aurora Metallic).

Asus ZenBook UX305C is available in three colour finishes

Asus ZenBook UX305C is available in three colour finishes

The grey model tested exhibited bad staining on its circular-textured bodywork after only casual handling, and care may be needed to prevent a ZenBook from becoming a greasy eyesore.

One deviation from the Apple blueprint is the manner in which the bottom edge of the screen folds below the main body to form a rear foot for the laptop on the desk. This adds a millimetre or two to the rear height – good for a tiny improvement in keyboard comfort – but it does mean the hard metal contact points can scrape along the table surface, and will inevitably become scuffed themselves with use.

Asus continues to fit the wrong shaped display to the range, in line with other Windows laptop makers that pull generic 16:9 LCDs off the shelf rather than use the appropriate 16:10 ratio display that the chassis was designed around. As well as depriving the user of useful vertical screen estate it introduces unnaturally thick bezel surrounds above and below the screen.

Note unequal spacing around screen, with overly letterboxed 16:9 screen leaving fatter bezel top and bottom

Note unequal spacing around screen, with overly letterboxed 16:9 screen leaving fatter bezel top and bottom

A new addition to the ’305C now that Windows 10 has landed is an additional infrared (IR) laser and camera, fitted in the bezel space above the screen alongside the usual 0.9 megapixel webcam. The IR laser and sensor are designed to map your face in three dimensions for biometric login, marketed by Intel as RealSense and by Microsoft as part of Windows Hello. This facility was not tested.

The keyboard is standard issue fare, tablet-style and now, unlike its predecessor, with rudimentary backlighting. Thankfully the trackpad has been improved enough to make it usable – the previous model’s trackpad was jittery and unreliable, to the point that a paying customer would be justified in asking for a refund. Basic steering and clicking was not perfect but good enough to get by.

Aside from a small lift in processor performance, as revealed in most benchmark speed tests, the UX305C is now offered with an ultra-high resolution display made from 3200 x 1800 pixels. On a 13-inch screen, giving a pixel density of 276 ppi, this is overkill, likely specified to impress naïve buyers who equate more with better. Sadly the ‘more’ here is a also likely the reason for the laptop’s underwhelming battery life.

Colour gamut is not bad, measured at 97 % sRGB, and 74 % Adobe RGB, although contrast ratio disappoints after a plummet from around 860:1 in the previous UX305F to just 350:1 in the sample tested. This contributes to a more washed-out display than its forerunner, even if its contrast remains a league ahead of budget Windows laptops saddled with 100:1 (and worse) screens.

For storage this ZenBook has a 128 GB M.2 solid-state drive, a 80 mm-long version based on SATA Revision 3.0 rather than PCIe. Wi-Fi comes courtesy of an Intel Wireless-AC 7265 adaptor, which has the good grace to work with two antennae and as many spatial streams, giving it potential for a maximum wireless sync speed of 867 Mb/s.

Three USB 3.0 ports is a useful number on a laptop this size. Missing are any higher-speed options like USB-C with Thunderbolt. A micro-HDMI port on the right takes care of external monitors and projectors. There’s no built-in ethernet although a USB 3.0 adaptor is included in the box, along with an attractive nylon slip case to cover the laptop when travelling.

In use the ZenBook proved relatively stable in Windows terms, with just one blue-screen crash experienced when calibrating the display, plus issues with one game while testing graphics performance.


Raw performance of the Intel processor with an 8 GB memory quota was measured with Geekbench 3, which showed a single-core result of 2442 points, and 4858 points multi-core. That’s a small lift above the 2188 and 4323 points of the UX305F; or around 12 % improvement, about what can be expected from increasing CPU clock from 800 to 900 MHz.

Alongside those results in line with expectation, PCMark 8 mostly returned similar small upticks in speed. The Home unit scored the UX305C with 2002 points in standard mode, and 2415 with the benefit of OpenCL graphics acceleration.

Any score too close to 2000 points or lower is cause for concern, although last year’s UX305F scored 1982 and 2344 points respectively so there is a measurable improvement here.

Turning to the Work unit of PCMark 8: the 800 MHz model scored 2408 (conventional) and 3366 (accelerated) points, while this year’s 900 MHz Core m ZenBook fell back to 2210 and 3192 points.

The integrated graphics processor in the Core m chip has been updated from Intel HD Graphics 5300, to Intel HD Graphics 515. The specs look the same – 300 MHz base clock on both; maximum increased from 800 to 850 MHz. Real-world gaming results were noticeably improved… when the game could play.

In Tomb Raider (2013), framerate for 1280 x 720 and Low detail rose from 31 fps to 43 fps, a significant move in the right direction. With Normal detail setting, framerate moved from 28 to 32 fps.

However Batman: Arkham City had problems completing the benchmark level. The sequence would pause and crash at the same point midway, but after some perseverance it completed with 42 fps (1280 x 720, Medium), against the previous model’s 25 fps.

The reason for fitting a low-power processor like the Core m is to reduce wasted heat, thereby eliminating the fan, and conserving the limited energy available from a 45 Wh lithium-ion battery. Longer runtimes away from the mains charger is the goal.

Shame then that the new ZenBook UX305C lasted for less than 7 hours in the same test that saw the UX305F run for close to 10 hours. With an HD MPEG-4 film looped and played back over Wi-Fi, and screen set to 120 cd/m², the latter ZenBook ran for 9 hr 58 min against the new revision’s 6 hr 51 min.

The 100 words or less

The latest ZenBook UX305C looks to be the ‘new-and-improved!’ take on last year’s UX305F. The price is around the same at circa-£600, and graphics tests suggest a useful boost to gaming ability, even if it’s still limited to the lowest resolutions and coarsest textures to keep framerates fluid. The CPU and display pixels advertise bigger numbers, and overall system performance was fractionally ahead of the earlier model in most tests, although the sexy 3200 x 1600 display has poorer contrast ratio and may contribute to battery life dropping by a couple of hours.

Andrew Harrison


Product code: UX305CA-FB005T

Part number: 90NB0AA1-M02050

Specification as tested:

13.3-inch (3200 x 1800) 276 ppi matt anti-glare display (Samsung SDC374A / 133YL04-P02); Windows 10 Home; 900 MHz Intel Core m3-6Y30, 2.2 GHz Turbo (2C/4T); Intel HD Graphics 515; 8 GB (2 x 4 GB) 1600 MHz LPDDR3 RAM; 128 GB M.2 2280 SATA Revision 3.0 SSD (Lite-On CV1-8B128); USB 3.0 ethernet adaptor included; Intel Wireless-AC 7265 (2×2); Bluetooth 4.0; 3 x USB 3.0; micro HDMI; SDXC card slot; stereo speakers (B&O-branded); 0.9 Mp webcam plus IR laser/camera; mic ; 3.5 mm headset jack; UK tiled keyboard with backlight; 105 x 73 mm buttonless trackpad; 45 Wh lithium-ion battery, non-removable; 45 W wall-wart mains charger; 323 x 225 x 12.9 mm; 1200 g