The EVGA SuperNOVA 850 G6 wins in 4 out of 9 comparable specs, with 2 ties. Its biggest advantage is Modular (50% better).
Pure Power 13 M 750W wins in 3 specs (12VHPWR Connector: 100% better).
Recommendation
Choose SuperNOVA 850 G6 if you want the best overall performance — especially modular.
Choose Pure Power 13 M 750W if 12vhpwr connector matters more to you.