in not really professional or anything here but i did somethings that makes the game much more smooth.
1) i just added the game to the nvidia control panel's 3d setting (should be same for others i guess) then i switched the power management mode to maximum performance (keep changing stuff there, it may help even more).
2) at the control panel, "detail" section, i choose the game to high priority.
your game may be much smoother by now. atleast, thats what i did to make it work. if you know all of the following, then im sorry for wasting your time.