Mission freezing and slow loading

[Xhylar]

Ever since the most recent update 18.14, I've been experiencing huge fps freezes and slow loading problems during missions.  So far fps drops only happens when I go into a large room or when a pack of enemies spawn within the area.  As for the slow loading, at the end of the mission it takes me to a black screen then after about a minute or so it shows the actual loading screen that takes twice as long.  I tried changing to DirectX 9, 10, and 11 and optimizing cache but still made no difference on both problems.