We've heard estimates of around 900,000 Surface RT sales, but it appears Surface Pro could be faring slightly better. Bloomberg reports that Microsoft has sold just over 1 million Surface RT devices, with the company shifting around 400,000 Surface Pro units in just over a month. If the figures are accurate then it shows that customers waited for the more powerful Surface Pro device over opting for the Surface RT which does not run legacy applications.

Bloomberg says Microsoft ordered around 3 million Surface RT devices, a figure that falls inline with previous rumors from The Wall Street Journal. Microsoft's Surface RT doesn't appear to be selling as well as the company might have hoped, but until Microsoft starts to share numbers it's hard to judge exactly how well its entry into PC hardware is doing.

Microsoft is not officially commenting on Surface sales figures, but Tami Reller, Windows CFO, has previously suggested the company would "provide some updates on how things are going" in due course. Panos Panay, Surface general manager, recently revealed to The Verge that "demand is higher than we initially intended for Pro to be." Microsoft had some early issues meeting supply, which appear to be resolved, but Bloomberg's figures suggest that Surface Pro is off to a better start than Surface RT.

The software maker is now working on future generations of Surface, with Panay admitting the company has previously investigated a number of concepts "beyond just tablet." A 7-inch tablet seems highly likely, especially given Microsoft's competition, and there's always a possibility of a Surface laptop.