I have found that at 750MHz the miner works best with 9.4 Volts. 8.8 is probably too low.
9.4v is a lot of power draw. Doing 9.4 volts you're drawing a lot more power than I really want to. The point is to keep the voltage low and the hashrate high because if you draw a lot more power the point of mining at a faster speed diminishes because your paying for a lot more electricity. At 9.4v the miners can draw up to 2100 watts of power...