If you have a slow torch, like I've read most people do. I made mine a lot faster by going into the Engineering screen (Escreen). It has never been really slow, unless I was downloading something or using an app, but after going into the Escreen quite a bit to recover lost memory it actually made my phone do everything a lot faster. I've never had a phone that went this fast, and I'm not joking.
Yes it is, but I always go into the screens I mentioned. I've looked in every other one as well, but don't mess around with anything else, except some other things that I know aren't going to hurt my phone or I back it up before I do.