Custom resolution

Hi all
I have an external monitor on my laptop and I’m trying to create a custom resolution of 2560x1440 in Ubuntu but it’s completely impossible as xrandr commands are not compatibles with nvidia drivers. I tried to update xorg.conf file manually but didn’t get the new resolution for my external monitor.
Do someone get a method to add it?
I have a Quadro K4000M with Nvidia drivers version 460.91.03

Thanks a lot