my system right now is evga gtx 780 acx running on +13mv oc and 4.4ghz 4700k, psu is just 700w 80+ bronze rated, and im planning to go for gtx 780 sli. monitor as of now is single asus vg248qe @ 144 hz , im just getting ready to play witcher 3 next year. so if im gonna get another gtx 780 i need to upgrade my psu. so any recommendations on my psu. tnx