Sony's VAIO range has long been associated with ultraportable laptops, and the 11.1-inch VAIO X-Series VPC-X11Z1E/X is one of the most extreme to date.

With a chassis that measures just 16mm in depth and weighs an amazing 775g, it's the most portable fully-fledged laptop we've seen so far.

The screen is stunning, with a pin-sharp 1366 x 768-pixel resolution. Unlike Sony's Atom-based VAIO P-series, text and icons are clear and easy to read, and it's great for watching films on or working with a couple of documents open side by side.

It's also a bright and colourful panel, and reflections are well suppressed.

The dimensions are kept small through the use of an Intel Atom processor, which allows for minimal cooling and more compact packaging. The chip runs at 2GHz, and is backed by 2048MB of memory, but we found performance broadly similar to most current netbooks.

That said, it starts up quickly and runs smoothly, and files are easily accessed thanks to the use of a fast 256GB Solid State Drive (SSD). One of the biggest differences between this machine and a netbook is the design.

Along with the amazingly compact dimensions, Sony has used high-quality materials such as carbon fibre throughout, in order to keep the weight down. The result is a premium machine that feels every bit the executive toy.

A downside of the thin design on the VAIO X-Series is a chassis that flexes noticeably under pressure, however. With the entire front of the chassis filled by the battery, there's little here to provide strength, so the use of a protective case is a very good idea.

Compact keyboard

The keyboard features the same style as other Sony laptops, with the keys protruding through individual holes in the chassis. It makes it a little easier to type at speed, with mistakes less common.

It's not perfect, with a short typing action a result of the thin chassis, but it's better than many similarly sized laptops and netbooks.

The keyboard is set slightly below the palm rest, however, so you may have to adjust your typing style to strike the keys.

You'll find two USB ports for connecting peripherals, a VGA port for hooking up an external display, and two memory card readers, one supporting SD cards and the other Sony's Memory Stick format.

There's also a Gigabit Ethernet connection with a half-sized port that clips open fully when required. 802.11n Wi-Fi and 3G/HSDPA are also all in place for wireless connections.

The VAIO X-Series VPCX11Z1E/X may share its processor with cheaper netbooks, but there's a lot to separate this tiny machine. If you place portability and design above all else and money isn't an issue, then it's definitely worth a look.

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