i have the same problem. Question do you play with an xbox controller? If yes, try to plug it into the pc with a cable and see if that fixes the issue. Since a couple of weeks i have a problem that when played with a wireless xbox controller, the game lags and stutters a lot.
It is a problem with the program Microsoft GameInput. It is explained in this reddit post. This problem is not only with this game, but with many other games i tried.
https://www.reddit.com/r/XboxController/comments/1noggbw/xbox_one_controller_ruins_performance_on_pc_over/
Hopefully this helps.
