Sony VAIO VGN-TZ31MN in Laptops

Up until recently, Sony had the high-end ultraportable market almost to itself - but that lack of competition didn't stop it achieving great things. The VAIO TZ21 we reviewed in January impressed us with its incredibly low weight and unprecedented portability, even if the price put it well out of most buyers' reach.

Since then, though, the MacBook Air and Lenovo X300 have been launched, and they look set to steal some of Sony's market share. Its new TZ series laptop, then, should be aiming to defend this position, but has it got what it takes?

The new TZ31 shares the same compact chassis as its predecessor, but comes in slightly heavier due to a slightly more rigid case. That's not to say that its weighty - at 1.48kg, this is still one of the lightest laptops with an integrated drive on the market. Even with the charger, it weighs 1.6kg.

The TZ21's screen was impressive, so it's no disappointment to see it here unchanged. With a diagonal of just over 11in it seems incredible to get a resolution of 1,366 x 768, and especially with such great quality. Colours are vivid and the backlight dazzlingly bright.

Text is superbly clear, even with a battery-friendly dimmed setting. The screen surround is also slightly more rigid than the TZ21's, so we'd be less worried about transporting this in a soft bag.

The keyboard is very compact, but the quality is equal to that of many larger laptops. Keys have a surprising amount of travel, depress gently and give good feedback.

The diminutive size of the keys means that a single finger tip covers the majority of each, but because it mimics the MacBook's keyboard there's a valley around each that avoids accidental key presses. With laptops this small, usability is pushed to the limit, but Sony has done a great job to squeeze the most out of the space available.

Again, with the trackpad, space is at a premium. It may measure just 38mm tall, but it still pushes the mouse buttons to the very bottom of the chassis. Despite this they fall comfortably under the thumb when typing, and are protected from accidental pushes by a thin strip of plastic at the front of the case.

The front of the case also features a cluster of switches and buttons. A hardware wireless switch on the front turns off Bluetooth and Wi-Fi, and a full set of media buttons control audio playback.

Unfortunately the rightmost of these is an eject button, which can accidentally be pressed by a protruding belly. These media buttons also control the Instant On feature, which lets you play music and video without booting up.

Upgrade options aren't normally a consideration with ultraportable laptops, but the TZ31 nonetheless offers an ExpressCard/34 slot, two USB ports and a mini FireWire port. There are Memory Stick and SD card slots too, so roughly five times the number of options provided by the MacBook Air.

While the TZ31 is comfortable to use, extremely portable and has an unrivalled battery life, there is a trade-off with power. It feels nippy enough, and applications load without delay, but the 1.2GHz ultra-low-voltage U7600 processor failed to break any records in our 2D benchmarks.

It scored 0.62, which isn't bad for a small laptop, but it can't match the recent offerings from Lenovo or Apple. The X300 scored 0.68 and the Air 0.69.

So, has Sony done enough to defend against the newcomers to the ultraportable market? The laptop is an impressive package, representing a slight but welcome update to the TZ21. It may be thicker than the razor-thin Air, and slightly heavier too, but it offers a host of useful ports and an optical drive, which Apple has had to sacrifice.