So I'm running an iPhone 3G on 4.2.1 and at first after I JB it was fine. I re JB broke it to add multitasking, but since then it has been extra slow, though it sometimes speeds up, but then again just to slow. Also, I notice as soon as I do any type of multitasking, even just hitting reply to an SMS if I am in a different App, it will springboard crash. Anyone have any idea why or what I can do to fix it? Thanks.