Originally Posted by
MJN SEIFER
It's not an emulator, it's the real PS1 disk, used in a PS3.
The PS3 doesn't contain a PS1's full hardware. It uses software to emulate the features of the older system. As such, even with a pristine game disc, there can be differences between the way it's handled by a PS3 system as opposed to the original PSX. How the software translates the files, how they're optimized for use with the processor, etcetera. Things change, and thus the results change. Sometimes these changes are small, unnoticeable, or even beneficial (such as faster load times). Other times, though, they can distort things in an undesired way.