I have 4 cubes running on 3 different power supplies, an Antec 1200, a Corsair CX750, and one on a Rocketfish 500W I had lying around. Right now, switching the clock to high makes no difference in the speed -- they all hover around 29.5GH/s, whether in high or low. When I set up the first one, it did overclock up into the mid 30's...  then I got distracted setting up the rest, and never really noticed when everything changed. Any ideas at all? I'm not sure where to start on this one.