I'm not sure if this is a bug in the software, or whether there is some funky things going on with the card's themselves, but voltages seem to set themselves where they please. My 2 cards have fairly comparable ASICS qualities, one is 78% while the other is 74%. Setting voltage to 1.25v on them = 1.031v for 78% ASIC and 1.063v for the 74% ASIC card. Here's another weird thing I noticed, the card running 1.063v actually pulls 5w less at the wall while hashing at the same settings. Seems like the higher ASIC card actually has more leakage. Increasing clock speed will also increase the GPU's voltage by it's self. Let's say for example: 1.25v set 1000mhz clock = 1.063v after vdroop using gpu-z. Up the clock speed to 1100mhz and now gpu-z measures 1.120v or so. To get back to 1.063v,youll have to lower voltage in GPUTweak to 1.15 for example. Those aren't actual numbers, but you get the gist of it. What's worse is that both cards behave differently!