I have an iphone 3G on version 4.1 and it is very very slow. However, when I do a turn off/on the iphone, it is faster for a few minutes and then I have to turn off/on the iphone again. I do this process at least 4-5 times a day. Its soooooooooo frustrating. The iphone is jailbroken. Should I just restore back to 3.1.3? Any suggestions or advice would be appreciated.