Now I am choosing between Chieftec GPM-850C (850 W, 80+ Gold, single 12V rail, but only 2 PCI-E power cables with 2 connectors each, totally 4, just what we need for S5) and Chieftec APS-850CB (same 850 W, 80+ Bronze, 2 12V rails, but it has 4 (!) separate PCI-E power cables). Both has the same price. I would like to combine them and buy a PSU with 850 W, 80+ Gold, Single 12V rail and 4 separate PCI-E power cables. For same price... But we are living in non-ideal world...
So the question is: will it be OK to use Chieftec GPM-850C with S5, keeping in mind that it has 2 PCI-E cables instead of 4?.. Cables looks solid, but...
Definitely go with the 850C should be fine. It would be better to have four full cables, but the S5 is relatively low draw anyway and the connector is the weakest point of the system. Go for the higher efficiency single rail supply.
Also, I don't speak Russian, but
this seems to indicate that one rail on the CB series feeds the PCIe plugs and the other feeds the MB and EPS plug. The 850CB is 40A/rail, but depending on the overcurrent protection on each rail you might need to butcher cables if you want the extra margin on top of 480W DC.