Comment 14 for bug 811240

I had this problem as well. I found that a very temporary (as in only takes effect while you're doing it) is to interact with the machine. It stalls on bootup, and I press keys (it seems like numlock, cntrl, and alt work the best) and it continues working.

I also have the same problem while running the system, and I press a key or touch the touchpad and it continues working. I stop interacting with it, it either stalls or runs very slowly.