My FPS has dropped from 30-45 FPS, depending where I am, to 13-22 FPS after the latest patch. Many of my clanmembers reports the same thing, 30 FPS -> 10-15 FPS. According to reddit and it appears it be happening to others as well. I do believe it is not as extreme for everyone, one friend only reported 5-7 FPS drop from 30.
This is a very unspecific issue. What do you devs need from us to find out whatever is causing the FPS drop?
Edit; I think the most extreme case we have in the clan is a 20FPS to 3 fps.