^^^ Did you have some strange idea that 4.2 was going to be more than just the SMS/MMS tone update? Did you bother to read any of the threads about the 4.2 GM edition and the preview of what exactly was included in the update? What exactly were you expecting to change in the "OS load" as you called it? Apple says "Improved performance" in every update because they include various streamlining updates with every OS update...
As far as your question about jailbreaking and "what does it do", do some homework there bud, a loaded question if there ever was one.
Sorry thought this was a forum where we could discuss what other users have experieinced with jail breaking.
Ive been reading the various threads about jailbreaking but I just want to see what the likes and dislikes are.
I did read the Apple release of what the iOS included on the new update.