I had to because the old one didn't know it was an Xbox 360. Put a 360 game in and was told to play this game useing a Xbox 360.

Anyway, the first game I tested the new box on was Fallout 3. The point here is that there was a slight difference in play between the two boxes. The old one when unlocking didn't require fine turning the lockpicking skill so it was very easy to open very easy locks. However playing on the new box, even very easy locks required fine turning the lock pick. I know it is a small thing but any idea why there is a difference?

Welcome to the forums, the point where you succeed at lockpicking is random each time so you may have just been lucky when you picked locks before.