$500 to $1000 per board? HF would be asinine to try and charge that. The good news is a user could simply by their own gear. User needs to supply power supply and cooling module. $60 per board for cooling module and if the boards use 250W to 300W ea that is 1/4th a 1250W PSU or say $80 per module. So maybe $140 per module or $640 for four, plus some DIY case and a couple screws. Someone would be downright stupid to pay $4,000 for that.
4 modules might fit comfortably into two pc chassis. if 4 modules fitted into only one pc chassis, hashfast would already be doing it. presumably the physical space for the radiators... and the airflow for the coolers doesn't work out well trying to cram 4 rads and 4 modules into a tower chassis, hence why they only put two into a baby jet and three (with one double decker) in a sierra, with twin atx power supplies - which is a custom case with room for the two psus.
so, two decent tower cases... $100 each? (total $200) if each module uses approx 1w/gh (as per their latest spec on the sales sheet from a few days ago at Inside Bitcoins conference) and each chip clocks at 500 GH... then for each two modules you need 1000 watts. if you include the fans, pumps, psu losses, controller etc... then lets say 1200 watts should cover it. two 1200w platinum psus approx $300 each (total $600). two raspberry pi's (one for each chassis) with sd cards etc $50 ea (total $100). Two Corsair H80i coolers ($100 each) so, if you build it yourself... your cost of parts alone, with you mounting the MPP 4x modules is $1,100. So presumably hashfast would easily get away with charging circa $1500, to offer to build it for you and save you time and hassle (and their buying power would give them a better margin than you could get from new egg). And i suspect they could easily charge more... and many people would take it, to know it was done for them and working.
