Same problem, but mine has a 780 GTX (flashed). Runs smooth as butter (pegged 60fps usually) in windows on same machine, but always under 30fps in OSX. Other games run fine at max/ultra settings in OSX, so I don’t think it’s just a driver issue, unless unreal is using driver features that most games don’t touch. I’ve noticed that if i combine every editor panel/tab into one single window (move all tabs together for material editor, etc) i get mildly better performance, but still nowhere near what it should be.