Sony VAIO VGN-Z51WG/B

Where would-be rivals resort to low-voltage processors and do away with such fripperies as integrated optical drives, the Z-series is the sensible old codger of the bunch. It happily conceals an optical drive - with a Blu-ray drive proving one of the many customisation options up on Sony's website - and the 2.8GHz Core 2 Duo P9700 processor makes no concessions in the power stakes.

Indeed, you'd be forgiven for expecting a 1.5kg ultraportable to lag a little, but that full-power processor really hammers along when the occasion demands it, and with 6GB of DDR3 memory and a 64-bit copy of Windows 7 Professional installed, the VGN-Z51WG/B proved its mettle with 1.43 in our benchmarks. Compare that to the raft of CULV rivals and there's only one winner.

It's also testament to the VAIO's sheer brilliance that such power goes hand in hand with unparalleled stamina. The first trick up its sleeve comes in the form of a switch above the keyboard to change between Stamina and Speed modes. In the latter, the Nvidia GeForce 9300M GS graphics are active, and the Sony managed a fair 26fps in Crysis at 1,024 x 768 and low settings.

But flip that switch back to Stamina mode and the discrete graphics chip powers down, handing duties over to the integrated Intel GMA X4500MHD chip. In tandem with Windows 7's Power Saver mode, with the optical drive powered down via Sony's proprietary power management software, the Sony clung on for an astounding 10hrs 1min of light use. It's a startling achievement, and in stark contrast to the 1hr 33mins of life when all those beefy components blaze away at full pelt and the screen is at maximum brightness.

Unless you're using the VGN-Z51WG/B outside in the height of summer, you're unlikely to need that brightest setting. The panel might measure just 13.1in across, but it's amongst the best we've seen. The spacious 1,600 x 900 pixel resolution offers outstanding brightness and superbly accurate colour reproduction, and the only slight let down is a little backlight leakage along its top edge.

Try as we might, there's little to criticise the Z-series for. The addition of a fingerprint reader adds a welcome element of security, and even the presence of Windows 7 helps to amplify the VAIO's charms. Swapping between the two graphics chipsets, for example, is now almost instantaneous and the overall experience is just that bit slicker and more satisfying.

The VGN-Z51WG/B outstrips the best of the netbook and ultraportable worlds for sheer longevity, but is also capable of switching gears and assuming desktop duties with its reserves of power. With Intel's mobile Core i7 looming large on the horizon, it mightn't be long before an even more flexible successor arrives, but right now, if your budget can stretch to it, the Z-series remains as good a laptop as we've had the pleasure of using.

Price when reviewed: £1,592 (£1,831 inc VAT)