On December 11th Microsoft announced that it had sold more than two million Xbox Ones, and it only took until the end of the month for that number to jump to three million. Since our launch, demand for Xbox One has been strong, Microsofts Yusuf Mehdi says. Sony, meanwhile, had previously been selling PlayStation 4s at roughly the same pace as its main competitor — it took the PS4 16 days to reach 2.1 million units sold, whereas the Xbox One reached a similar milestone in 18 days.