is ok 2 corsair ax 1200 i platinum?
that would be my PSU of choice. without having looked at the exact spec, i'd assume that would suffice to power your new Neptune.
Why need to use 2 1200W?
I think 1 1200(1300) and 1 850W is OK
if use 1x 1200w and 1x850w, how to connect to the 5 box + 1 controler?
1-st option - 2pc 1200W PSUs - one Psu for 3 boxes - another for 2 boxes + controller -> one 1200w PSU - work with 3 boxes
2-nd option - 3pc 850W PSUs - (one PSU for 2 boxes)x2 , another Psu for 1 box + controller -> one 850W PSU - work with 2 boxes
1300W+850w is OK
I'm with 1 1300w (3 boxes + controler) + 1 850W (2 boxes)