Question Monitor won't show 144hz w/ displayport.

[amphi19]

I'm currently using a 2560x1080 ultrawide that won't let me use 144hz. I'm using a display port and 144hz worked until recently. Another thing to note is that if I change my resolution to 1920x1080 etc. it will let me use 144hz, just won't work with the ultrawide res. Help?

 

[Barty1884]

Which GPU do you have? And which monitor, specifically?