old gen cpu

Hello, I'm new here, but I've been struggling with decisions and information about upgrading GPU for Lenovo Ideacentre AIO Y910 system. System specs now are: i7 6700 (non K) Gtx 1080 16gb ddr4 2133mhz 500gb ssd 380W PSU ( currently playing RDR 2 computer consumes 270W max from outlet) This...