Each iteration of Intel’s Centrino line has brought incremental improvements in battery life, performance and, often, both. The technology behind Centrino 2 promises much in terms of better battery life, courtesy of Intel’s 45nm Penryn-class processors. While these should also bring with them a slight uptick in performance, the great leap is likely to be withheld until the beginning of 2009 with the introduction of Intel’s next-generation Core i7 CPUs.

The first of the new line of Centrino 2 laptops through the PC Authority doors is the Asus M51, which was announced and demonstrated at Computex in July, showing off the possibilities of WiMax.

But, although it’s a native component of Centrino 2, it’s going to be some time before WiMax makes its way into mainstream laptops. However the M51 does have 802.11n, so it’s compatible with the long-range routers on p62.

The M51Va might not be the most stylish 15.4in laptop we’ve ever seen, but its sleek silver and black lines and textured trackpad exude affordable class. With only a little flex in the lid, the construction is solid, and the chassis feels robust enough to withstand a decent amount of force.

The recessed black keyboard has well-sized keys and is deep, if not quite as crisp as we’d like while typing. It can become relatively loud during spells of energetic typing, but in general we were pleased by the lack of noise. It’s comfortable, too: its depth and size makes typing comfortable, even for extended periods.

There’s also a number pad; something not often seen on laptops with screens smaller than 17in, which will be useful for programmers, gamers, and spreadsheet aficionados.

The M51’s excellent usability continues with its trackpad: it’s a smooth-as-satin number with good glide and a responsive feel. The fingerprint reader between left and right buttons – standard on this range of laptops – takes a little getting used to while navigating applications and we found occasionally activated it accidentally.

The rather chunky bezel, which integrates a 1.3MP webcam, gives the impression that the 1440 x 900 widescreen is small, but the 15.4in, 16:10 screen gives plenty of usability. It’s bright and clear, with accurately-reproduced colours. The only drawback is the resolution precludes 1080 High Definition output.

The optical drive is similarly constrained. Most users won’t mind: it’s a super-multi drive, rather than Blu-ray, but High Definition capabilities are something we’re beginning to expect from performance-focused laptops. The omission seems doubly odd when you consider that the M51 includes an HDMI port.

It’s not just the omissions that had us scratching our heads. The M51Va includes 4GB of RAM, yet another in a growing list of laptops with more RAM than a 32-bit operating system can optimally handle – a large chunk of the RAM is rendered unusable by hardware memory addressing. It does, however, allow a reasonable amount of future-proofing – this is a laptop that will conceivably be able to handle the next version of Windows.

We’ve no complaints about the basic ingredients, either. The fast Core 2 processor and all that RAM helped the M51Va blitz our benchmarks. The overall score of 1.4 is phenomenal, and the fastest we’ve seen for a laptop; the next closest is its close relative, the Asus M50SV, which ran to an impressive 1.32 on our benchmarks back in April. Compare it to the Dell XPS M1530, the outgoing A List resident, and it’s a clear leap ahead of that model’s 1.04. There are no two ways about it, this is a powerful laptop.

Despite all that power, the M51 remained surprisingly cool during testing, with barely any heat detectable on the underside of the chassis. There was the odd blast of hot air from the back of the laptop via the fan and pipe cooling system, but you’re unlikely to notice this unless you deliberately get in the way.

Performance from the Radeon Mobility HD 3650 was just as good. In Crysis, at 1024 x 768 and our lowest settings, it ran to an average framerate of 46fps - this much power from a comparatively cheap portable is a good thing.

The downside to all this power is battery life. Intel’s claims about Centrino 2’s battery life haven’t quite materialised in this system, with the M51 running to just one hour and 24 minutes in our intensive test; under minimal use it ran for two hours 24 minutes. Enough to get through a DVD, but not to see any of special features or buckle down to work.

Despite a few shortcomings – most notably its mediocre battery life – it’s hard to beat the M51 for performance. We also appreciate the balanced spread of specifications and the two-year international warranty. And, its build-quality and external features will all be major pluses. Its superiority in all the areas that matter means it passes the Dell XPS M1530 on the A List.