must hash 60gh without issues.
You realize you are asking more than a U3 can deliver, right? "Without issues" does not exist where the U3 is concerned. Save your coin and wait for the gekkoscience pod miner...
Haha I was hoping there were a few that could mine without going into zombie. Looked at the gekkoscience stick, but it's too expensive for what it is. Just found the pod thread (thanks for the heads up)