For a long time I was looking for the reasons for the sudden brakes in the game (previously everything was stable)... I found in the English forum a problem with the priority of Ubisoft services, namely UplayWebCore eats more than the game itself with high priority, thereby fps drops sharply during the game (not just in menu, namely in the game), you need to fix this manually, in the task manager - details, reduce the priority on all UplayWebCore to Low, and also select only one physical core in the similarities. I noticed that this procedure helps with lags or dead freezes/abrupt crashes of the game, but the ubisoft overlay works/updates slowly, although this is not critical...
5.5