When Ultrabooks were first introduced by Intel, one of the first models to show us that they could stand up to the gauntlet laid down by the Apple MacBook Air was the Asus Zenbook UX21. There have been plenty of other great Ultrabooks since, including the Acer Aspire S5.
It hasn't taken long for Asus to supercede its older models, though, with the Zenbook UX32A appearing at the lower end of the spectrum and the Zenbook Prime UX31A as the show-off premium model.
The Asus Zenbook Prime UX31A continues the styling of its predecessors, with brushed aluminium being the order of the day. The material has straight lines on the bottom housing, while the back of the screen has circles that catch the light.
It's got a faintly industrial look, but it all feels impressively solid. There's no give in the build, the hinge holding the screen is nicely stiff, and it's comfortable.
The Asus Zenbook Prime UX31A remains one of the best-looking Ultrabooks around. Though you can certainly see the MacBook Air's DNA in its design (especially the tapered profile and those new black, rounded keys), it maintains the look of the original Zenbook.
It's a shame to be stuck with the Intel and Windows stickers on the front, but they are at least monochrome again.
Intel's contribution to the Asus Zenbook Prime UX31A is a Core i7-3517U processor, running at 1.9GHz and featuring the latest Intel HD 4000 graphics. It's accompanied by 4GB of RAM, all used to power Windows 7 at this point.
The most notable change in the Asus Zenbook Prime UX31A, though, is easily its screen. The UX31A boasts a 13.3-inch, 1080p IPS wonder, dwarfing its competition for resolution.
Being a high-end Ultrabook, there's an SSD powering its quick boot and resume times. You get a 256GB drive in this version of the UX31A, and unfortunately, there's no way to boost that up to 512GB, no matter how many lotteries you've won.
Connections-wise, Asus has included a decent selection, provided you don't mind the occasional adaptor. There's a micro HDMI port and a mini VGA port, catering for your analogue and digital video output needs.
There are two USB ports - one on each side - both of which are USB 3.0. There's a headphone port and a power plug, and rounding it off is a card reader compatible with SD and, er, MMC. Just in case anyone out there's still using it, we guess.
Asus has also included its ICEpower speakers, the result of a collaboration between Asus and Bang & Olufsen.
This high-end Asus Zenbook Prime UX31A is priced at around £1,500/$1,500 online, bringing it right in the firing line of Apple's highest-end MacBook Air and the Samsung Series 9. In fact, both of those two come in cheaper by default, but it's important to note that the Zenbook Prime offers a faster processor and higher resolution screen.
Although Asus insists that the Zenbook Prime UX31A is a mere 9mm tall when closed, that's not entirely accurate - the body is, but it has feet to raise it off the desk and keep its vents clear. This still means it slips into small bags easily, but in reality, it stands about 2cm off a table.
It is impressively light, though, coming in at about 1.2kg.
There's also a lower-end version of the Asus Zenbook Prime UX31A, with a Core i5 processor, 128GB of storage and a 1600 x 900 screen, instead of the 1920 x 1080 beast in the high-end model. It comes in a fair bit cheaper.
There's also the Asus Zenbook Prime UX21A, an 11.6-inch version of the Zenbook Prime that still features a 1080p display.
Intel's Core i7-3517U processor has appeared in a few high-end Ultrabooks, including the Samsung Series 9 and Acer Aspire S5, so it's no surprise to see it in the Asus Zenbook Prime UX31A.
It's a dual-core chip, but features Hyperthreading, so has four virtual cores. Its rated clock speed is 1.9GHz, but it can be pushed all the way to 3GHz with Intel's Turbo mode.
Perhaps most importantly for a laptop with a 1080p display, it's an Ivy Bridge chip, and so features Intel's latest and greatest integrated graphics. HD Graphics 4000 might not trouble a dedicated card for grunt, but it's plenty powerful for HD video and casual gaming.
Along with the processor, you get 4GB of DDR3 RAM, clocked at a healthy 1600MHz. While this should be plenty for standard Windows use, this amount of RAM - along with the dual-core processor - are a reminder that this isn't intended to be a portable workstation.
The solid state drive is SATA 3, so is capable of taking advantage of the speeds of its flash memory. The 256GB should be enough for most people, but that's not what you get in practice - only 140GB is available for data. This is likely to prove to be an issue for those with large music or video collections.
It's a handy thing, then, that Asus has included two USB 3.0 ports, making it easy to transfer files to and from the Zenbook Prime very, very quickly.
Bluetooth 4.0 is also included, and there's built-in Wi-Fi, of course. There's no Ethernet port, most likely for size reasons, but you can buy an adaptor.
Speaking of adaptors, the micro HDMI and mini VGA ports offer video output, but you'll need to make sure you have the correct connectors, since neither is included in the box.
Of course, the Asus Zenbook Prime UX31A's own screen is nothing to be sniffed at. It's a 1080p IPS display - something you rarely see in 13-inch laptops at all, let alone in Ultrabooks. Though it doesn't quite reach the extreme pixel density of Apple's MacBook Pro with Retina display, it's still an extremely high resolution for the screen size. And, being a Full HD display, it's 16:9, so is ideal for watching movies and TV shows on.
Adding to the multimedia credentials is the Bang & Olufsen-powered speaker system.
There's no optical drive, though. This is hardly surprising for such a thin machine, but it does mean you can't make use of that Full HD display to play Blu-rays without buying an external drive.
Benchmarks :
Cinebench 10: 10729
3D Mark 06: 5330
Battery Eater 05: 144 minutes
Cinebench 10: 10729
3D Mark 06: 5330
Battery Eater 05: 144 minutes
It's easy to pick out the best part of the Asus Zenbook Prime UX31A - that screen is excellent. It's reasonably bright, with appealing, natural colours - but as you might expect, it's the resolution that's the killer.
The 1080p screen is extremely crisp and detailed for the display size - you'll almost certainly want to turn the text scaling up in Windows, or you'll find yourself edging increasingly closer to the screen while you work, as we did.
And, yes, movies look very good indeed on the 1080p screen. The contrast ratio is good, motion is handled well, and there's plenty of detail in everything.
The viewing angles are excellent as well, and it's nice and bright, keeping everything clear.
Going beyond the screen, the Asus Zenbook Prime is no slouch when it comes to Ultrabook performance. The 1.9GHz Ivy Bridge CPU offers up impressive Cinebench results, even compared with many of its competitors using the same processor.
The result is that it comes across as plenty powerful for multitasking, as long as you stick to standard Ultrabook stuff - you won't exactly be rendering Pixar's next movie on it.
That's compounded by the 4GB of RAM - it's nice, fast RAM, but anyone hoping to do significant video editing or similarly intensive tasks will probably find it constricting.
For just about all home computing use, though, the Asus Zenbook Prime UX31A is extremely responsive, and works its way through most tasks with ease. It runs the 64-bit version of Windows 7, too, so is really eking the most out of its Core i7 chip.
No small part of that speed comes from the SSD, of course. The Asus Zenbook Prime UX31A can turn on in just a few seconds, and resumes much faster even than that - we're talking just a couple of seconds, if that. This has always been the goal of Ultrabooks, of course, and you'd hope one that costs as much as this would nail it. And let's be clear - it has absolutely nailed it.
Using the keyboard is great, too. It's not quite perfect - the keys are a tiny bit soft for us - but it really isn't too far off. The keys feel a good size, are fairly responsive and are separated well, making them easy to hit, and are backlit.
Backlighting often seems like a minor thing, but it's something you always miss once you've had it. Some cheaper Ultrabooks leave it out, but here at the premium end of the spectrum, Asus has made sure to include it.
The trackpad is a big clickable square, and works well. There's a small line at the bottom to denote where buttons might have been in the past, but its purpose is just to show you where to click for a right-click. For left click, you can just click anywhere else.
By default, you can just tap the Asus Zenbook Prime UX31A's trackpad to select something, but we found this a little overly sensitive for our tastes. Multi-touch support is also built in, and pinching and scrolling worked well for us.
The much-touted Bang & Olufsen speaker system is a real disappointment, sadly. They're clear enough, but there's no depth or warmth at all in music from them. It sounds tinny, sometimes a little shrill, but it does the job for dialogue in videos. Explosions are flat, but it's clear enough.
But it's not the biggest problem with the Asus Zenbook Prime UX31A - not by a long shot. The battery life is really disappointing. We like to see Ultrabooks get 200 minutes in our Battery Eater 05 tests, but the UX31A managed only 144.
One of the main purposes of Ultrabooks is to be all-day work machines, but the Zenbook Prime falls badly short in this department.
The original Asus Zenbook UX21 really helped to make the case for Ultrabooks, showing that if you want a speedy, thin, light laptop you don't have to buy an Apple MacBook Air.
The Asus Zenbook Prime UX31A is a natural successor, with a faster processor and graphics, and additional USB 3.0 port, more storage space and that vastly upgraded screen.
The result is that, unsurprisingly, the Asus Zenbook Prime comes with a premium price. And it very nearly meets it with a premium product, but falls short in one very important area - the battery.
We liked :
The Asus Zenbook Prime UX31A's screen, of course, is the big showpiece. It's not just the resolution, but the overall quality. Great colours, excellent viewing angles, good contrast ratio - at 13.3 inches, it's a 1080p masterpiece.
Performance really is just as speedy as you'd hope, with Windows 7 picking up almost instantly from standby, and even booting barely giving you a wait.
Really importantly, it's also comfortable and pleasant to use. The trackpad is good, the keyboard is great, and it's made really well.
We disliked :
There's one major and obvious letdown with the Zenbook Prime: the battery life. Though in practice, with very light use, you'll get more out of it than we did in our benchmarks, it's still badly behind the competition - even the much, much cheaper competition.
The speakers are disappointing, too, and it's a shame that Asus includes so much irritating bloatware on its machines.
The price is an issue, as well, especially in light of the battery life. The Asus Zenbook Prime UX31A isn't inherently overpriced at £1,500/$1,500 when you compare it to other high-end Ultrabooks, but you have to ask whether you're happy spending that much money for this kind of machine.
For many people, it'll be secondary to larger, more powerful computer - you'd have to ask, do you really need to spend this much? And if you do, will the battery life be good enough for you?
Final verdict :
The Asus Zenbook Prime UX31A is a premium computer with a price tag to match. The build quality is excellent, the performance is great for an Ultrabook and the screen is top-notch.
Sadly, the battery life makes you think twice about its good points when you're spending that amount of money - we're just not sure that it's worth it for all that many people.
If you want a high-end Ultrabook, we recommend the Asus Zenbook Prime UX31A as long as battery life isn't your main concern. If you just want an Ultrabook, we suggest starting a bit lower, with its little brother, the Asus Zenbook UX32A.
