Well, actually that's numbers can be valids, because if you do the math with 32 1Gbit ddr3 1866 module*3 (4GB per board) then 32*3*14.9/192*30=~223.5Mh/s (=~7x RX 580).
I came up with ~250Mh if they have optimal straps on ddr3-1866. When it comes to power consumption I expect it to be well under 1000W. I have no intention of buying one, and I'm not at all concerned it will render my GPUs worthless. I might even be able to buy a nice new Rx580 for < $200 then.