Microsoft, citing several internal retail sources, says that the Xbox 360 flavor of Rockstar’s Grand Theft Auto IV is outselling the PlayStation 3 version by a ratio of two-to-one.

Product manager for Microsoft, Aaron Greenberg, believes the promise of future exclusive DLC with GTA IV 360 is “making a big difference” in the purchase decisions of consumers.

That’s making a big difference in peoples’ console purchase decisions. … GTA fans are switching over to Xbox 360 just like Guitar Hero fans and Madden fans did. …The same thing is happening with Grand Theft Auto IV.

In terms of raw in-game statistics, Greenberg said that nearly 1 million members logged on Live to play GTA IV online the day it was released. Additionally, users unlocked 2 million achievements within 24 hours of the game’s release, amassing over 15 million Gamerscore points.

MS: 360 GTA IV Outselling PS3 Version 2-to-1 [Next Gen]

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Read more: GTA IV First Week Sales Total Half A Billion,  Variety: Rockstar’s GTA IV To Shatter Game Sales Records,  Rockstar Promises “New Multiplayer Modes, Weapons, Vehicles” For GTA IV DLC,  First GTA IV Review Hits the Internet,  GTA IV Development Costs Totaled $100 Million, Outnumbers Shenmue