Corsair RM850x High Performance Power Supply. Corsair RMx series power supplies give you extremely tight voltage control quiet operation Gold-certified efficiency and a fully modular cable set. Built with all Japanese 105 C capacitors theyre a great choice for high performance PCs where reliability is essential. 80 PLUS Gold efficiency reduces operating cost and excess heat and Zero RPM fan mode ensures virtual silence at low and medium loads. And the fully modular DC cables make builds and upgrades easy with clean great-looking results.