I found my 6 GTX 1070's at 60% power profile (120 core, 720 memory) consumes 760W which on the Silverstone 1000W PSU (1100W peak) will do the same (i.e. restart) occasionally. I only run two riser cards off each SATA power rails and two off molex rail as well. Benefits of gold or platinum rated PSU certainly matters, so when I can afford it I'll like upgrade my PSU to prevent the issue of my mining rig restarting.