Well, OCZ GameXstream is basically a Fortron Source Power (FSP) FSP700-80GLC which is a very well reputable PSU manufacturer, they also make PSU for other famous brands. But I think we deviated too far off topic, but back on topic.
Its interesting the fact that the GTX 460 1GB consumes slightly less power than the GTX 260 and yet is faster, but its interesting the fact that the GTX 460 is never twice faster than the GTX 260+ considering it has more than 50% of everything except bandwidth and texture performance. May be with newer drivers, it can take advantage of the hybrid super scalar approach of the GF104, I'm a still bit skeptic after they failure with the NV30 and its superscalar architecture. It would seems that while nVidia drivers might be slighly better, AMD's compiler within the driver are much better.