Hey, I'm getting a great smooth constant fps everywhere with everything ultra 2560x1440p with SLI GTX 780.

Except for whenever there is a campfire nearby, my FPS plummets, the moment I extinguish it smooth sailing.

I've been trying to find which setting is causing the campfires to bumrush my FPS but to no avail, anybody getting this problem? Trying to determine if it's specific to my hardware or not.