So increasing the voltage makes the card more or less stable?
Whats the rule of thumb?
700mhash at 1175 was about right. That said, getting to be summer here so I have dropped to stock speed and undervolted some to reduce heat and save on the electricity and A/C bill, which brings it down to around 555mhash.
More voltage allows higher stable clocks, but also increases heat generated (and electricity used), and heat in turn can make the card less stable. Basically voltage will make the card stable at higher frequencies if you have enough to cooling to deal with the extra heat, to a point.