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Alexandre Botella Published on February 18, 2011
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  • CPU Intel i3-380M (2.53 GHz)
  • Graphics chipset NVIDIA GeForce GT 415M
  • RAM 3 GB
  • Screen 13 inches, 1366 x 768 pixels
  • Storage space 3.2E-7 GB
  • Optical drive NA
Let us introduce you to the Asus U31JG, with its 13.3 inch matte panel, core i3 processor, dedicated graphics card and, according to the manufacturer, impressive battery life. Should the MacBook Air 13.3 inch be sweating? 

Design and build: finish needs a second look

Although entirely in plastic, the U31JG has a sober and relatively elegant design. The finish could obviously be better however. Much like the Medion ERAZER X6811 that we tested recently, the shell tends towards being overly flexible and sinks in all too easily when you press down on it. It's fairly resistant to finger marks though, with only the sides of the panel and the keyboard susceptible to being marked. The rest of the plastic is matte.


Apart from the overly flexible shell, the keyboard on this 13.3 inch is irreproachable. Typing is supple and quiet. The keys are well-positioned and correctly proportioned and keying errors are rare.

The multitouch touchpad is of good quality and precise. The glide is fine (pleasant) though it certainly wouldn't have gone amiss to extend it a few centimetres.

Compaq Mini 311cThe webcam is no model to follow. The image is pixelised and movements lack fluidity. Anyone buying this laptop should really consider opting for an external webcam too.

Asus has limited connectivity to the essentials so as to keep this ultra as lean as possible. On the right there's a VGA out, an RJ45 port (Ethernet), an SD card reader, an HDMI and two USB 2.0 ports. On the left you'll find the power socket, a USB 2.0 port and the headphones and mic sockets.

The U31JG's fan runs very quietly. The only way you'll hear it is if you stick your ear right against the chassis, which means you won't annoy anyone working in the same space as you, or be troubled when watching a film. Temperature levels are well controlled. Even when you put a lot of demands on it, the temperature remains under the 35°C mark.

Fluke ti25 distrame%281%29

The U31JG's temperature readings when you push the components hard
Readings taken using a Fluke Ti25 (Distrame) camera

Underneath, with the panel off
V130_dessous Hood

  Power supply, USB 2.0, headphones and mic out/SPDIF 
USB 2.0 port (x2), HDMI out, SD card reader, RJ45 and VGA out

Processor power: good performance

The U31JC has a dual core Intel Core i3-380M processor. While the CPU's name is similar to that in the Vostro V130 (Core i3-380UM), the 380M is nevertheless a good notch higher in performance terms. The 380UM scored 52 on our index, whereas the 380M scores 93.

In practice this 13.3 inch is perfectly at ease with multi-tasking usage and everyday office documents. It also performs reasonably with 3D modelling, retouching photos and 3D video editing/encoding.

You can play HD 1080p (Blu-ray equivalent) no problem on this machine. Whether using the processor with its integrated graphics chipset (Intel GMA HD) or its dedicated graphics card, the U31JG is up to the mark. Best to opt for the Intel GMA HD if you can, using software such as Power DVD 9, VLC or Media Player Classic HC for the graphics card hardware decoding.

Note that this ultra portable comes with Optimus technology. Developed by NVIDIA, it allows you to switch automatically to the NVIDIA graphics card when the integrated chipset is over capacity. Once the demands on graphics resources have dropped again, Optimus switches you back to the Intel chip to maximise your battery life.

Windows 7 Pro 64-bit takes 45 seconds to boot. You'll need to wait another 10 to 20 seconds for the various background applications to start running (antivirus off). It turns off in 12 seconds.

Gaming: limited capacity

With the GeForce 415M, a mid-range card, the U31JG has limited gaming capacity. In practice, it does honourably with a few undemanding games but the more recent titles only run at minimum graphics settings and, more often than not, at low resolution.

Audio: thankfully there's the S/PDIF

Don't count on the U31JG's speakers to give great audio. What comes out of them is frankly mediocre and lacks volume. The headphones out is much more convincing. Thankfully there's an S/PDIF connection, with means we can give it a three star rating.

Battery life: a nice surprise!

When it comes to battery life, you're in for a pleasant surprise. The U31JG lasted 5h45, which makes it a match for the Macbook Air 13.3-inch, which gives 5h43 under the same conditions (Wi-Fi deactivated, headphones plugged in and brightness at 100 cd/m²).
At 1.8 Kg, this 13.3 inch model is a good travelling companion. It slips easily into a rucksack or bag and it's light enough to be carried with you all day.
The screen:

Good news first. The U31JG has a matte panel. Even at low brightness (this screen has a max of 134 cd/m²) you can use it outside without having to flee the rays... as long as you're reasonable.

The 13.3 inch screen has a resolution of 1366 x 768. Characters are a good size and and you won't suffer from too much visual fatigue.

TN technology is used here, with ghosting equivalent to 5 ms models. Viewing angles from above and below are therefore narrow, alongside responsiveness that's sufficient for working on office documents and viewing films. This is a shame for a gamer machine, but is unfortunately all too common.

Default colours are poor, with a Delta E of 9.8 and a very marked colorimetric shift towards blues. Contrast is also bad - as with most current laptops - with a ratio of 239:1. We measured the black level at 0.56 cd/m², for a white of 134 cd/m².

To correct the colours you can download a calibration profile from our profiles page, though we can't help you with the contrast.


  • Battery life: 5H45 video playback
  • Excellent CPU performance
  • Keyboard and touchpad comfortable to use
  • Matte panel
  • Quiet


  • Panel with very low contrast (234:1) and inaccurate colours
  • Finish not great


It's really a shame that the finish on this model doesn't do justice to the performance under the hood and the excellent battery life (5h45). Poor finish aside, this is an excellent ultra portable laptop.
4 Asus U31JG DigitalVersus 2011-02-18 00:00:00
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