Consider it the Halo: Reach bump. Previously, the Xbox 360 enjoyed three months of strong sales thanks to a hardware refresh, but Bungie's 343 Industries' franchise has been known to move consoles, so it's no surprise Microsoft dominated September. Greenberg elaborated in his following tweet that Microsoft sold 483,989 hardware units in September, "a 37% increase over last year." He also claimed the console is the only system with higher sales year-over-year.