2. The twin, non-redundant power supplies are a waste of space & a sign of sloppy, afterthought engineering. 3 modules in the case? 2 power supplies? One module gets one, and remaining two get the other? Two power supplies to provide 750W? Honest?
There are no *single* off-the-shelf PS which could handle 750W? They had to enter into a contract with Sea Sonic to provide them with *TWO ANEMIC PSs per box"? Really?
I'm not saying that the whole thing will fail on the merits of its cooling solution alone. It likely won't -- 750W is not a huge amount of power to dissipate. What i *am* saying is this: If their cooling & packaging design is indicative of their ASIC skillz, what we have here is a giant fail.
correct me if i am wrong, but isn't the total more like 1400watts per unit... and you cannot get a good efficient PSU that is 1600, so 2*850 were choosen?
also, if 2 pci cables power each miniboard, then you can have a pci cable from each PSU powering the 3rd board.
According to Hashfast, their chips draw .65W/GH/sec, so: .65 * 400 * 3 = 780W. Let's round it off to 900W to make up for fans, pumps & fluff. Sea Sonic, the company Hashfast has entered into some sort of a deal with (PR release is unclear), has platinum-rated 1000W gizmos available @ Newegg @$239.
As far as running two power supplies in parallel, it might work, and it might be fireworks/one PS "loafing" at idle & not adding to the fun -- depending on the output circuitry of the PS. It's possible to bridge switching PS, but not worth the effort.
Hope this helps.