The Corsair RM1200x SHIFT wins in 3 out of 9 comparable specs, with 4 ties. Its biggest advantage is PCIe Connectors (200% better).
SF850 wins in 2 specs (Efficiency: 25% better).
Recommendation
Choose RM1200x SHIFT if you want the best overall performance — especially pcie connectors.
Choose SF850 if efficiency matters more to you.
