Each title will vary re: what'll impact graphical quality proportionate or disproportionate relative to system resources.
Typically selecting a "max", "ultra", "epic" preset for example, with crank up shadows, AA and Phsyx among other things. And those (again, typically) can be reduced to varying degrees to lower the resource requirements, while not actually impacting much to the eye.
Not a game I'm overly familiar with, but from what I can find..... on capable hardware relative to the resolution, "Epic" presets are aiming for 60FPS..... Low can be >200FPS. A balance of Medium-High should net you an improved experience, without impacting much at all.
If that doesn't fix anything, it may be an issue with your rig (either hardware-wise, or software/background tasks etc).
Please post your full system spec.