Microsoft has refreshed its tablet line-up with a new entry-level device that runs more software, but is also more expensive than its predecessor. The Surface 3 is powered by an Intel processor, unlike the ARM-based chip in the Surface 2- this means that it uses the more user friendly Windows 8 operating system, rather than the more limited Windows RT. The previous bigger tablet, which was launched 10 months ago, features a 12in (30.5cm) screen, compared with the 10.8in display of the new Surface 3.