chrisp99 :
Right i hear you there that 512mb thing. Can you do 4k on your 390?
LOL, everything can do 4k, though only a few things can do 4k adequately. I don't have a 4k monitor, and I only really care about perceived slowness (judders, lags, etc) on my 2560x1440 (Acer XG270HU)
Skyrim maxed with many mods is so very, very nice. Other games I play casually are World of Warships and, well, the League of Dungeonering. WoWS cause the fans to spin up, but it's still very nice.
My 260X did Skyrim on the 1440p monitor but at less than maxed settings (all at about 80%) at about 50-60 FPS average. I'm assuming that the 390 could go 4k with slightly reduced settings and still be enjoyable.