850w from either of those brands should be plenty, im running older more power hungry 780's and an overclocked 4790k on a 1000w sf leadex platinum. Seeing about 620w max total system and monitor power draw at the wall when gaming. The evga G2 psu's are simply rebadged superflower units, but with a stonking 10 year warranty. This would swing it for a lot of potential buyers.