Quote from: bitly on December 14, 2013, 06:36:50 PM

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The disadvantage of using Bitfury chips is the low "GH density". PCB size = 12cm x 12cm ? If boards are spaced 1cm apart = 144cm3. 42 GH per board. 0.29 GH/cm3 or 3.4 CC/GH. Fluorinert runs about $0.80 per CC ($80 per Liter), thus at 3.4 CC of fluid per GH the fluid cost is $2.72 per GH which is pretty high. The higher the GH density the less fluid needed per unit of hashpower and the more economical the system. My goal would be to get fluid costs to <$0.25 per GH and full system cost (excluding SHA-2 boards) <$0.50 per GH.

So it's really not the chip but rather the PCB design that is "low GH density". If we could redesign the PCB, it may achieve a much higher density and much smaller volume?

actually, i'd be worried that the high GH chips from hashfast and cointerra (300-400 watts per chip) would be too hot in terms of spot heat, and you might need some heat spreader thing to increase the surface area.

the low GH chips from bitfury et al will be no problem for immersion cooling.

even the knc chips, medium heat (150 watts per chip).. will need some kindof heat spreader

Also, when choosing the heat spreader, you will want to find one that doesnt stick out too much so that it doesnt affect your board density in the bath. ie: long thin heat spreaders may be more useful than the high tower heatsinks that knc currently uses on their board with an air fan