1. They overclock the CPU, GPU, or both.
2. Faster phone.
3. This isn't what you want to hear, but since the only other person on this board with a skyrocket (that I know of) is viva, I would probably say that you should go to XDA or rootzwiki and see if anyone else is having such a problem and how they are taking care of it.
(i.e., my Evo 3d doesn't have this issue, so I can't help you)