yeah, well.. my 290x only displays 60 75 or 100 on a 144hz monitor (34gk950)
edit: don't tell me that the 290x uses DP 1.2 and maxes at 100hz..
already did that. officially, dp1.2 supports 2560x1440@144.. so 344x1440@120 wouldn't be much of a problem. even setting the resolution to fullhd won't let me select higher refresh rates (than 100).
fun-question: did you enabled DP 1.2 in you monitor menu? (with the buttons on the monitor)
like with my AOC G2460PF i had to do this myself ;)
mh, did you connect DP and HDMI? or only DP?
maybe try a different cable ;)