My recommendation, for now, is to aim for no more than 725mhz on the S17 and not to go beyond 19.6 volts until more results come in. But at 700-725mhz and 19-19.2 you should be achieving 65-70th/s. Which is a fairly good performance gain as it is. If there is one thing I learned a stable overclock is better than a powerful overclock. When auto tune is out I would say play a bit higher but for now I suggest everyone plays it safe.