Trying to squeeze a heap of high-power components into something slim enough to earn the name ‘laptop' is always a challenge, and portables have traditionally been the slow-witted cousins of the PC family.

Reducing power consumption and waste heat is the biggest challenge, and that's more easily tackled when you have a large chassis to work around. So the fastest portables have traditionally been those with hulking bodywork and matching big screens. Add some flashing lights and a hot-rod trim, and you ought to have a gamer's dream. But looks can be deceptive.

The market for gaming laptops has moved up a notch in recent months, with some manufacturers managing to shoehorn quad-core processors into their portables. As we've discovered when testing desktop PCs for our Top 5 charts, however, the software world is not entirely ready for more than two cores. To get the best out of these designs, your applications and operating system will need to be optimised for multithreaded use.

The cost is predictable - and not just financial. Quad-core laptops are expensive in comparison with dual-core designs, but they also tend to be long on excess heat and short on battery life.

An even more pressing concern may be the question of how useful those extra cores are for playing 3D games anyway, as few titles will make good use of them. When it comes to pushing pixels around the screen, it's still really the GPU that calls the shots. This month, PC Advisor has had two quad-core gaming laptops in the lab: the Asus G71V and Rock Xtreme 780.

Given its huge size and impressive features list, the Sony Vaio VGN-AW11XU also ought to be a good contender for unbridled real-world performance. We just weren't prepared for how good. Thanks to its 2.8GHz dual-core processor and 128GB Raid-configured solid-state disk, the Sony pulled off the highest performance score we've ever measured in a laptop.

Not that far behind, and at half the price, is Dell's new Studio XPS 13. This is also quick: quicker, indeed, than many a desktop system we've tested. The surprise here is that all that firepower comes packed into a svelte laptop, with a 13in screen and great design touches such as a backlit keyboard and leather and aluminium trim. This is no normal Dell doorstop.

For the Studio XPS 13, beauty is not merely skin-deep; it permeates through the design. Its raw performance makes it a viable, and truly portable, replacement for the modern desktop PC.