FPS 30 lock ?

When im fighting the finals boss in act 2 the game for some reason lock at the start of phase 2 on 30 FPS. I fought the boss on 30 FPS and died. I tried alt tabing etc it did not fix it and the only choice I had to close the game and reopen untill its fixed.


On the other hand my friends in party they have older hardrware and they did suffer a crash.


In act 5 I had a similar issue in one of the maps I cant remember but it was locked at 40 fps.