Wierd performance issues

Since the DirectX12 renderer was introduced i was really satisfied with the performance 'cause i didnt have to play with disabled audio anymore and could still play on steady 60 fps.
Now after the 200 MB bug fix patch i cant even stand in my hideout without having 50 fps and in maps i have only 40 and thier really incosistent.
How can a 200 MB patch completely fking wreck my performance...