On the box it said that the monitor supports 144Hz, but I've been using HDMI for past few months so I got 70Hz max. Yesterday I bought DisplayPort cable in hopes od gettting 144Hz, but instead I got 75Hz max (so only 5Hz more). My graphics card is Nvidia GTX 1060 3GB, resolution is 2560x1440p. Even on smaller resolutions max option is 75Hz. I tried setting refresh rate manually through Nvidia CENTROL panel but got to max 77Hz and then the display said no signal. I also tried reinstalling drivers.Have you made sure that you have enabled G-Sync\Free-Sync compatibility in the Nvidia control panel? I know that some monitors' higher refresh rates are only unlocked when using these technologies. Just a thought.Yes I enabled (and DISABLED) G-Sync, it made no difference. The only thing is that when I had a HDMI cable the G-Sync wasn't even an option, now wtih DP it is, but refresh rate is still low.It looks LIKE my monitor only supports 75Hz, because of the part number on the back: UM.HG0EE.A01 despite advertising it as 144Hz.Well that's terrible news. I hope you are ABLE to return it without HASSLE... Good luck!That is a 144Hz monitor, what cable are you connecting with?