Via has said that the current versions of ultra-mobile PCs (UMPCs) need more 'fine tuning', and that the next generation will be smaller and lighter - a point echoed at Winhec by the head of Microsoft's UMPC division.

Its C7-M ultra low voltage chip is used in the Pace Blade Easy Book E7, a rival to the Samsung Q1, which is based around an Intel Celleron processor. Within months, Via-based UMPCs will include the VX700 chipset, enabling manufacturers to improve on the design.

The tiny devices are central to Microsoft's Origami concept of Internet-connected mobile computing any where at any time from any location.

Running Windows XP Tablet edition, and weighing around 1kg, with screens about 7in in size, the handheld devices will start hitting UK streets in June.

Colin Brix, chipset platform group international marketing specialist, said although such devices will find strong markets, the next generation will have better battery life, slightly smaller screens, and be 'half the thickness' of the current crop.

'Some of the first models we are seeing are not at their optimum,' he said. 'The technology is there, but for early devices they are really rushed.'

Battery life for the Via-based Pace Blade (which we have yet to be given to test in our labs) is a claimed 2.5-3 hours. 

Via claims it low-power chips are more energy efficient, and so have greater battery life than devices using Intel's processors. In PCW's tests on the Intel-based Q1, the battery lasted around 2.5 hours, although less when purely used for watching video.

Neither device is good enough for all day usage. Heavier long-life batteries can be added, but UMPCs will need greater battery life to fulfill their potential.

First generation devices are using low-power CPUs, and although faster processors can be used instead, this adds to the cost – which is already above Microsoft's hoped-for price – and reduces the battery life. But this will need to be cracked if they are to run Microsoft Vista once released.

It was expected that the Via-based Pace Blade would undercut substantially the cost of the Q1, because its processors are cheaper than Intel's. But in the UK the Easy Book E7 sells for £750, just £49 less than the Q1.

The Windows Tablet machine comes with a 40GB hard disk (which can be upgraded to 100GB), 512MB memory and runs a 1GHz Via Esther CPU.

Blix said the manufacturer, and not Via, sets the price of the devices: 'We sell the chips cheaper [than Intel]. Whether [manufacturers] want to save that cost and pass it on to customers – that's their choice.'

Although battery life and power need improving, the overall concept of UMPCs is impressive, and the Q1 performed well in our tests.