Well, I tried that in both games, ETS2 and Pathfinder but didn't notice any improvements on the stuttering side. ETS2 only goes up a few FPS, depending on the area I am in, while Pathfinder seems to be capped at 90 FPS after disabling vsync and it also stutters a lot when moving.
I searched info on Pathfinder and it looks like it's a Unity game and several people have issues with framerate even on way better HW than mine.
I also started playing Metro: Last Light Redux on GOG, very high settings, vsync enabled and it's running great, super smooth.