I have been ripping my cds to my ps3 in 320 mp3 format for a long time now but just noticed that some store bought cds of similar length rip to much different file sizes. For example Biohazard - State Of The World Address @ 57'33'' rips to 54MB and Black Sabbath - 13 @ 53'33" rips to 123MB. My guess is cd production quality but i can't find any immediate notes to this in a google search. If this is the case, by how much and how often do bought cds vary and if not, then what is the reason for the different file sizes. Also if they are starting off at different quality then how come they don't rip down to the same quality if all i am suppose to be getting is 320 mp3 as the final ripped product?