New monitor, various problems

[Savage One]

I've for a long time had two 1080p 60Hz monitors. Today i bought a 1440p 165Hz monitor, replacing one of the previous. Firstly, i can only get it up to 144Hz in Nvidia control panel, i am using a displayport cable. Secondly and most importantly, I have only play one game thus far that properly works/scales. GTA 5 is 70% a black bar all the way around the game itself, yes i pressed ALT+Enter and swapped res and every other thing i could think of. Other games the mouse cursor is displayed in a place it actually isnt, so navigating menus is impossible for them. I beg you wizards to help me.

 

[Savage One]

To add, it seems to be a DPI issue, going to properties-compatibility.. i select "Overide high DPI scaling behaviour. Scaling performed by "application"" that seems to fix it but i have to do this for every game?