Chart-Track has reported that the sales of GTA IV helped the Xbox 360 far more than it helped the Sony PS3.
Chart-Track looked back at the sales of the Sony PS3 and Xbox 360 four weeks before the launch of GTA IV, and then compared those numbers to the post-launch sales numbers.
GTA IV helped increase Xbox 360 console sales by 47% in the UK, compared to only 8% for the Sony PS3.
This shows that at least in the UK, GTA IV helped out the Microsoft Xbox 360 a lot more than it helped out the Sony PS3.