Please, do elaborate, Syke. I'll admit, I don't know how it is impossible. I'm assuming you're talking about the constraints of design and expected performance improvements with a node size shrink?
Yes, that's the biggest issue. The shrink from 28nm to 20nm will give roughly a 25% improvement. If they tried to do 6 TH/s, it will be because they are using many more chips, and it would be expensive, and the power draw would be in the 5,000+ watt range. That's simply not going to work.
Thanks, Syke. I appreciate the explanation. However, if KnC can achieve even .75W/Gh, at 6Th, that is sub 5000 watts. Is .75W/Gh out of the realm of plausibility? I'm wondering, since it is widely know, that as BTC mining returns are inevitably becoming increasingly narrow, electrical efficiency takes a larger precedence. If Jupiter was a race to get the largest horse out of the gates the soonest, and Neptune is to get the most efficient horse possible, they may take more time refining Neptune than they did Jupiter. More board revisions; better efficiency. Could hoping for under .75W/Gh be a pipe dream?