US retailers inform Microsoft that the multi-million selling title is selling three units on Xbox 360 to every two on PS3.

Grand Theft Auto IV screenshot

According to data provided from the US Xbox team to Gamerscoreblog, retailer information indicates that sales of GTA 4 in the US favoured the Xbox 360 by 3-to-2.

Other info from the US Xbox team reveals that Xbox 360 console sales at retail went up 54% week-over-week as a result of GTA 4, and retailers are telling MS that roughly 40% of new Xbox 360 buyers are also taking home a copy of GTA 4.

Gamerscoreblog has also posted a bunch of Xbox LIVE stats relating to GTA 4:

• In the first week, more than 2.3 million people played Grand Theft Auto IV on Xbox LIVE.
• GTA 4 is now the number one played game on Xbox LIVE.
• Over the weekend the Xbox LIVE service reached 1 million concurrent users.
• Gamers have unlocked more than 12 million achievements worth over 100 million gamerscore points in GTA 4.
• Grand Theft Auto 4 set a new record for time played, with the average gamer spending more than four hours playing the game on LIVE in the first week alone.

For lots more on Rockstar's latest head over to the GTA 4 game page.