I know what you mean, I had 50gb on my 60gb PS3 after I started it up. But I do know the why - 1) Hard drive marketing uses a rounded version of bytes for display. Like, I have a "300gb" hard drive that is actually only 279.5gb. 2) The file format takes up space, and 3) the XMB takes up space. So you probably ended up with about 70gb, and yes, all that stuff can take up 11gb.
EDIT: As has been said, you can see how much the game saves take up by going to the Saved Data Utility under Games. You can also see how large trailers are by pressing triangle on one and going to Information.
One time when I was playing Goldeneye for the N64 (when I was like, eleven), I got so angry at it that I ripped it out of the console, threw it across the room, then chucked the controller, and I was so angry that I just cracked up laughing as hard as I could, to the point of tears... But that wasprobably just my latent insanity showing itself.
Log in to comment