It's been clear for some time that Microsoft has lagged behind Sony when it comes to sales of modern consoles. However, it's been difficult to pin down the exact difference due to the paucity of public sales data. The best we've been able to do is report that, as of April, Sony had sold at least 7 million PlayStation 4 consoles through to consumers while Microsoft had sold just 5 million Xbox Ones to retailers. Today, Ars Technica took a stab at shedding more light on the topic in an interesting report that estimates Microsoft has sold no more than 7.5 million Xbox Ones worldwide since September, while Sony has sold at least a bit more than 10 million PlayStation 4 units it had reportedly sold through to consumers as of August. Ars had to do a bit of tricky number-crunching and guesstimating to come up with those numbers, since Microsoft has a policy of not distinguishing between Xbox 360 and Xbox One units when reporting sales of Xbox hardware. It's one of the best estimates we've seen to date, and it's worth your time to read through the full report on Ars' website for further details on how the sales figures stack up.