Simon, regardless of what you think is doable, you are taking unnecessarily high risks to develop such a high-TDP chip. It would have made a helluva lot more sense to go with, say, 4 chips of 63W each. The die would be 1/4th the size. 1/4th the cost too since you would have 4x more chips per wafer. A little more PCB space would be used (big freaking deal). But this would have taken away a lot of the risk of cooling a single hot chip.
The energy density (W/mm2) would still be the same. 1/4th the wattage over 1/4th the area. They had decided to go water cooling for efficient heat transfer. That would mean more complex asembly, more components, and higher cost. Not sure how that is going to improve ROI%.
There is a reason that Intel puts 4 cores on a single socket chip rather than having consumer grade boards run 4 sockets with single core processors.
I see this as a very poor strategic decision made by Hashfast. (And Cointerra, and KnCMiner). Only BFL seems that they will get it right, since their 350W Monarch card will split the workload across 10-30 chips.
BFL get it right? The PCIE card form factor is very tough. BFL will need to cool 350W using a single blower fan in a very compact space. This is a task that even AMD got wrong ... twice (6990 & 7990) resulting in 6 month delays on those cards. If you said Avalon, AsicMiner, or BitFury (easily cooled boards with multiple chips over large surface area) you might have had a point. I don't think "right" is the proper word (it is a design choice) but you may have had a point. BFL? You showed your true colors there.