Me and a friend have been having an issue with the game where we would get a consistently low FPS (about 9-10). At first we thought it was graphics settings causing it and started to play around with those to no avail (some of the settings forced us to restart). After testing some more we figured out that having steam open was the cause. We closed the game, closed steam and when we relaunched the game the framerate went back to normal levels.
We are both playing on PC via Ubisoft connect.