When Intel announced the development of a new, ultraportable platform, which would change the portable PC philosophy from the core, few anticipated the arrival of such devices as ultrabooks. Just as they created the netbook in their time, Intel opted for a new approach yet again and decided to change the concept of “portable”.

The ultrabook, as its name says, is a very peculiar category of portable PCs, one which combines the dimensions of a netbook or ultraportable notebook with powerful hardware, and all that in an exceptionally thin and light enclosure. We’ve received ASUS’ UX21E from the so-called Zenbook series (which consists of ultrabooks exclusively) as the first of this kind.

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It’s no less than fascinating that ASUS has managed to pack such strong hardware into an enclosure of such thinness and lightness. Reminiscent to when netbooks first surfaced, the size, hardware and appearance of ultrabooks is yet to be defined.

UX21 ViewTop H Right80 sOn the other hand, judging by the models that have appeared or been announced thus far, we can expect to see all-around firm aluminium casings, a very low profile, Intel’s latest Core CPUs, SSDs or HDDs, no discreet graphics, a minimal number of connectors, and extraordinary cooling systems.

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Accompanying bundle

Having in mind its exceptional thinness, the number of connectors on this model is pretty limited, so everything that you’ll come across is 2 x USB, mini-HDMI, mini-DP, audio and power connectors. In order to counter this drawback, ASUS has included two very important adapters in the bundle, together with a fine linen carrying bag for the two. One of them is USB-to-LAN, while the other one is mini-HDMI-to-VGA, which raises the value of this model by quite a bit, especially since connecting to projectors will no longer require expensive separate adapters (just think of MacBook Air, for instance).

The box also contains a very nice carrying bag/sleeve, designed in accordance with the Zenbook itself. It’s a thin letter-bag with a nicely coated interior and a very pleasant exterior, which doesn’t indicate the presence of a thoroughbred ultrabook inside. A most useful and thoughtful detail, in our opinion.


Even at first glance, Zenbook leaves one breathless. At second, too. Whether it’s the new concept, the fantastic design, the particularities of this very model or something else, the “wow” effect is definitely there. The thickness that ranges from an incredible 3 mm in the thinnest section to 17 mm at the bottom of the lid speaks volumes about Intel’s capability to achieve the desired results and boldly step on Apple-dominated territory in both dimensions and performance. The aluminium enclosure is made of large metal plates, similarly to the unibody design of HTC phones. Simply enough, there are no parts that can be removed in order to take a peek inside the PC. Everything is firm, tight and very compact, so don’t even bother worrying about crackling or bending. The choice of materials affects cooling as well as firmness and robustness, in that the entire enclosure acts like a giant passive cooler.

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The lid has a large ASUS logo as the centre of several concentric circles, which creates a unique visual effect. The lid is opened via a discreet bump on the top; until you’ve got used to it, the process may seem a bit awkward at first, as you don’t have anywhere to put your other finger on and help yourself a bit. The weight of the larger models is a redeeming factor in this respect to a certain extent, but that’s not the case here, so take your time in getting accustomed to this feature.

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After you’ve lifted the lid, you’re greeted with one of the most breathtaking designs we’ve ever seen. We’re not exactly sure as to whether it’s the combination of materials, colour, layout or all these together, but UX21E is bewildering. The display frame, lid and keyboard frame are darker than the rest of the casing, which we think accentuates the already excellent visual presentation of this model.

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If we have to split hairs and look for a negative remark to make, we would’ve preferred a thinner display frame, but rest assured than no one sane will notice this while looking at Zenbook. The 11.6” display has a resolution of 1366 x 768 (UX31E has a 13.3” display with a resolution of 1600 x 900), and has the all-popular glare coating, which could’ve been omitted for all we care. The viewing angles are strange to say the least – although the horizontal ones are as good as they get, even a minimal vertical movement will cause the image to degrade. Of course, as the lid is very easily adjustable, this flaw is easy enough to compensate for. We love the high resolution of the display, as it makes everyday tasks much more pleasant to perform.

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The display lies on the Chiclet keyboard nested in a metal “sifter”, which, coupled with bright keys, offers better visibility and readability of the keyboard itself, giving a faux impression of it being backlit, even. Some keys are actually backlit, however: Power, in the top right corner, F2, used to turn wireless connections on or off, as well as Caps Lock, all containing their own discreet LEDs in a corner of the given key. Although room is scarce, only the cursor keys have been minimised, but even they are very easy to manipulate with, as they’re physically separated from the rest of the keyboard.

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The keys themselves have a deeper travel distance than we’d like, so it may occur that you “swallow” a letter here and there if you’re accustomed to another notebook’s keyboard and type fast. From our personal experience, it’ll often happen that you hit the frame of a key rather than the key itself at first, which will make you think you’ve pressed a key, while no character will appear on-screen. As for shortcuts, most of them are organised in the traditional notebook manner, so that everything’s readily available where you’d expect it to. The only key that you may hit unwillingly is the Power key, which is located in the upper right corner, traditionally assigned to the Delete key.

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The central part of the palm rest carries a rather big touchpad (similar to MacBook Air models), with integrated accompanying buttons, but unlike the case with HP’s recently reviewed notebooks, these don’t act as part of the touchpad itself. Clicking takes a bit of getting used to, since it moves most of the touchpad surface, and the active section is very pleasant and precise – nothing to reproach in this department, therefore. The keyboard frame and the touchpad are the same colour as the keys, and have a ground metal texture, which contributes to the overall visual impression.

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The bending part of the lid consists of a central hinge with three functions. Besides connecting the lid to the body very firmly, due to the large surface this piece covers, it also contains a central Bang & Olufsen speaker, which, coupled with the two side drivers, creates a surprisingly loud and good sound image. The third function of this piece is opening the space for the netty part it lies on when the notebook is closed, contributing to the cooling system in ejecting the hot air more efficiently from the otherwise pretty crammed enclosure.

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If you thought you’d be able to open Zenbook, have a look under the hood, poke at the battery, change memory and so on, this won’t be all that simple, as the entire lower body is made out of a single piece, protected by an army of non-standard screws. Besides the impressive visual setting, an enclosure this compact and airtight has to cause heating as well, so don’t be surprised to feel more warmth in your lap than usual.


Core i7, SSD, prismatic cell batteries… All this is just a small part of what waits on the inside of UX21E. The latest generation of Core i7 CPUs will jump from the relatively low default clock of 1.8 GHz up to 2.9 GHz using Turbo technology with ease, as long as there’s need for it. The memory subsystem has a cosy 4 GB RAM, but don’t even think about expanding the available memory, as due to the dimensions of this model, the memory had to be integrated into the motherboard, making it fixed for good. HD 3000 is the integrated GPU inside the Core i7 taking care of graphics, and while you won’t be playing games to your heart’s content with it, it’ll do well with less demanding or older titles, as long as you’re willing to compromise in resolution and detail levels.

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On the other hand, gaming makes the notebook very warm, hot, even, so keeping it in your lap is not something you want to experience while playing. The lower, central piece seems to be the most afflicted by heating, which can be bothersome on more than a few occasions. All other tasks that don’t require the CPU to remain at full load for extended periods of time will cause much less heating, so office work, surfing the net, watching films and listening to music will make Zenbook warm at best.

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As for storage space, ASUS has opted for a 128 GB SSD, using the well-known SandForce SF-2281 controller, and achieving excellent results, which you can see in the charts. Although some will be glad to see results such as 550 MB/s in certain synthetic tests, we don’t see this feature as very relevant, as the SSD is primarily fast in everyday tasks and has a low response time, which makes Windows work comfortable, and that is the whole point of getting an SSD.

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Suffice to say that Windows 7 boots in about 15 seconds on this baby. Using an SSD also makes the sleep state a more viable option, as the system can become fully operation in seconds at any time, and this technology, which makes shutting down the system almost unnecessary, is called “Instant On” by ultrabook manufacturers. In practice, this really is a revolutionary new habit to have, as the notebook can go to sleep for several minutes or several days at a time, coming back into full functionality immediately when desired. No reboots, no power-ups, nothing.

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In order to achieve these dimensions, the entire motherboard and its components had to be redesigned, so not only are the memory and SSD integrated, but the battery was made using the prismatic cell technology, more on which you could’ve read on this year’s IDF report. In practice, due to the power-saving capabilities of all hardware components, autonomy ranges from just over an hour in full load mode, to just under six hours in power-saving mode.

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TrueCrypt 7.1 encryption/decryption [MB/s]
AES 238 / 239
Twofish 176 / 179
Serpent 120 / 116
7-Zip 9.20 compression/decompression [KB/s] 6.208 / 80.421
Blender 2.60 [s] 537
Cinebench R11.5 OpenGL [fps]/CPU/CPU (Single core) [pts] 7,91 / 2,18 / 1,11
HD Tune Pro 4.61 average [MB/s] 245,4
AS SSD Benchmark 1.5
Read 16 MB / 4 K / 4 K-64 Thrd / 512 B [IOPS] 31,82 / 4.171 / 28.956 / 5.451
Write 16 MB / 4 K / 4 K-64 Thrd / 512 B [IOPS] 8,24 / 10.964 / 33.716 / 2.957
Read Seq / 4 K / 4 K-64 Thrd  [MB/s] 509,12 / 16,29 / 113,11
Write Seq / 4 K / 4 K-64 Thrd  [MB/s] 131,78 / 42,83 / 131,7
Copy Benchmark ISO / Program / Game [MB/s] 114,5 / 85,67 / 127,07
CrystalDiskMark 3.01 x64
Read Seq / 512 K / 4 K / 4 K QD 32 [MB/s] 459,2 / 405,4 / 25,67 / 109,6
Write Seq / 512 K / 4 K / 4 K QD 32 [MB/s] 142,8 / 140,6 / 48,99 / 137,4
Battery Eater Min/Max 1h 18' / 5h 56'
3DMark Vantage Performance Score / GPU / CPU P1.470 / 1.161 / 7.272
1366x768 0xAA 0xAF
Street Fighter IV Med [fps] 42,4
Resident Evil 5 DX10 High [fps] 23,2

Thin, thinner, Zenbook

Small dimensions, a thin enclosure and small weight, combined with a stunning design, make for one of the best-looking, if not the best-looking, notebooks we’ve ever encountered. Small dimensions do bring a fair share of compromise with them, though, so you’ll have to settle for two USB ports, one audio connector and two video outputs, but that’s the price to pay for this kind of look.

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Furthermore, heating can be an issue during more taxing tasks, but having in mind the hardware contained within, that’s to be expected as well. There’s enough novelty and designer solutions on this model to outmatch even the accessories list on Dell’s Alienware models.

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If you’re expecting new technology to use its first models to penetrate the market and make way for later revisions, containing a bunch of issues and child diseases typical of such devices – you’ll find none of that here. Intel has done their part of the job flawlessly, ASUS has done their best to add their own touch to the concoction, and the result speaks for itself – Zenbook is a worthy introduction to the ultrabook age by all means. The only reason to keep you away from this PC is a high price, one that requires a more sizeable budget than usual.