GripnRip on 15 September 2010
Dude, RTFA! It specifically mentions that the 1st month for the PS3 was August 2009 and only takes into consideration the few days that some stores put the PS3 Slim on shelves early.
"The Xbox 360 S model clearly demonstrates growth quite similar to that of the PS3 Slim, even though the comparison isn't perfect. In particular, the first month of the PS3 Slim was just barely in August 2009, when some systems arrived in stores just before the end of the NPD Group's reporting period. So, while sales were up modestly, the full effect was not felt until September."
Regardless, both have offered a boost bigger then either manufacturer was probably expecting. We should be happy both consoles have sold so well.
