Performance Issues in Areas with Lots of Spell Effects

I know you've probably seen this posted a million times, but I really do hope one of the next major updates focuses heavily on optimization, because the quality of the mapping experience is wildly different.

I enter a crypt mission and consistently hit 144 fps (the cap I set). However, when I switch to a creek mission, which has a delirious effect, I'm unable to exceed 27-35 fps.

It is legit unplayable, because every 5 seconds you get stutters. I've completed all the fixes outlined online and have a fairly decent setup, but I still get constant stutters as soon as the map has any environmental effects, my FPS tanks through the ground.