Intel's low-power Atom CPU proves that, for most computing jobs, you don't need a fast multicore processor like a Core i7 or even a Core 2 Duo - you just need a little patience.

But patience won't cut it when it comes to graphics: for games and videos to be enjoyable they need to run smoothly and at full speed, and, sadly, standard Atom systems lack the power to deliver that. So while current netbooks and nettops are fine for office and internet tasks, they're all but useless for entertainment.

This isn't wholly the fault of the processor: a big part of the problem is the ageing Intel 945 chipset that accompanies it. In most packages it includes weedy GMA 950 integrated graphics, which lack video acceleration and don't support DirectX 10 at all. The more exotic Atoms - the Z500 series, intended for MIDs and nettops - get the more capable GMA 500, but as we saw with the Dell Inspiron Mini 12, that struggles with full-screen video too.

Nvidia's Ion: our test unit had a similar volume to a VHS cassette

Enter Nvidia, with the cleverly named Ion platform. In physics, an ion is a charged atom, and Nvidia's Ion is an Intel Atom system that's been powered-up with a GeForce 9400M in place of the 945 chipset and graphics.

Although the 9400M is new to the Atom, it's an established chipset that's already found in full-specification laptops such as the Dell Studio XPS 13 and the Apple MacBook.

And it's a more compact architecture than the Intel 945, which means Ion systems can be even smaller than traditional Atom devices - our test unit had a similar volume to a VHS cassette. Yet despite its diminutive design, Nvidia claims the 9400M delivers ten times the graphical power of the GMA 950.

Real-world performance
In practical terms, this means Ion brings true high-definition video to the Atom platform. The GeForce 9400M includes a hardware video decoder, and we noted a significant drop in the CPU load while playing back 1080p H.264 video: from close to 93% on an Intel system down to just 15% on the Ion, impressively drawing just 24W as it did so.

Other tests such as MPEG4 and native Blu-ray playback proved more of a strain on the CPU, but the Ion remained unflustered. Immediately, that makes it an appealing step up from the standard Atom.

The 9400M also brings full support for CUDA applications and DirectX 10, and Nvidia is keen to play up Ion's gaming potential, citing games such as Call of Duty 4 and Spore as examples of supported software.

But don't expect console-type graphical effects: the 9400M's 16 stream processors give it only half the horsepower of the 9600M found in more grown-up systems, and it won't come close to the graphical power of a discrete high-end card.

What's more, many modern games tax the CPU as much as the GPU, and here Nvidia's chipset is of no help: in our 2D benchmarks, our sample Ion system achieved an overall score of 0.30 - a bog-standard result for a single-core Atom system running 32-bit Vista.

So we weren't surprised to see Ion struggle in our 3D tests. In our low-detail Crysis test it managed a juddery 16fps; and in the low-detail Call of Juarez benchmark it averaged 10.4fps - a small step up from current Atom systems.

The shape of things to come
Although our test system took the form of a tiny box, Nvidia expects manufacturers to produce Ion-based systems of all shapes and sizes, from lightweight laptops to home media PCs and all-in-one desktops.

Real-world products have yet to be officially announced, but the platform has already gained Microsoft WHQL certification and the first retail product is set to appear imminently. Prices should start at $299 - that's around $360.

How these systems will fare remains to be seen, however. Intel itself has already announced an upgraded GPU for forthcoming Atom systems, dubbed the GN40. This, it promises, will also support smooth 720p video, at a lower cost and with lower power consumption than Nvidia's platform. If Ion systems don't establish themselves quickly, Intel may steal their thunder.

No matter how the battle plays out, the real winner will be the consumer. With the advent of full-screen video, cheap netbooks and compact PCs are taking a step closer to equalling the versatility of a full-power desktop. And that has to be a good thing.