It's 6.8 GB, like I already clarified years ago.

For example DD 3.5 inch diskette had a capacity of 1 MB, yet the MSDOS filesystem allowed only 640 KB, the same disc could hold 880 KB with the Amiga default file system and up to 960 KB with a more advanced, faster and modern Amiga filesystem later on.

For gaming data 6.8 GB is the 360's DVD limit. Just take notice of the file size when installed on harddrive.

Games which max out to almost exactly 6.8 GB storage include, Condemned 2: Bloodshot, Dead or Alive 4, Eternal Sonata, Fable 2, Ghost Recon: Advance Warfighter 2, GTA IV, Lost Planet, Madden 09, Mass Effect, Gears of War 2, NBA 2K9, GRID, Rainbow Six Vegas, Saint Row 1 & 2,  Splinter Cell: Double Agent, Warriors Orochi 2, etc.

All games using about 6.7-6.8 GBs, as that's the limit of 360 DVDs. No game can be found which requires over 6.8 GB per disc for this reason.

There are also a few (mostly early) 360 games, which stick to SL discs (games will load quicker vs DL). 360 games which are only about 3.4 GB of data, include Xbox Live Arcade Unplugged Vol.1, Two Worlds, Shikigami no Shiro 3, Raiden Fighters Aces, Raiden IV, PES6, Fight Night Round 3, Full Auto, Earth Defense Force 2017, Dark Sector, Command and Conquer 3, Blazing Angels, etc.

Condering the evidence presented to you, why do you think 3.4 GB and 6.8 GB are so common?

All comes down to preference. I'm just glad I have a pc also that can play L4D and Mass Effect, and Alan Wake, Splinter Cell: Conviction, etc. in the future.

Already posted. Locked.

Funny that you're talking about 3.5 " disk because I'm pretty sure I could put a bit more than 1 MB on those things and on Windows.