Question 144hz

[Lilgup66]

Hi, so i have a i5 9400 cpu and a Rtx 2080 super gpu. I just got a 144hz moniter and when i go see what its detecting at it says 60hz. I manually switched it to 144hz and games feel super laggy and dropped it down to 120 and felt the same. What could be causing this?

 

[RARRAF]

using display-port cable ??

 

[Vic 40]

Which monitor? Some will have hdmi that will do 144hrz, but might have two hdmi ports from which only one will support 144hrz.