So, I ended up running into the problem again today. It seems like it gets worse as time goes on, I'll have to test more and see if I can find the conditions to cause it. I will say that it happens in places where my framerate is usually buttery smooth, and when no zombies are on screen. Today I basically just walked out of the house and bam, 30 fps. If I walk away from the area, it's up to around 80. If I restart the game, 80. The first two were just me playing without any real problems. Walking all over the area where the framerate dropped substantially. The last was around when everything got bad, just look at that 16.8 fps dip.
06-07-2020, 00:51:05 7daystodie.exe benchmark completed, 11901 frames rendered in 140.485 s
Average framerate : 84.7 FPS
Minimum framerate : 57.3 FPS
Maximum framerate : 125.4 FPS
1% low framerate : 42.0 FPS
06-07-2020, 19:44:27 7daystodie.exe benchmark completed, 15479 frames rendered in 178.750 s
Average framerate : 86.5 FPS
Minimum framerate : 65.6 FPS
Maximum framerate : 126.8 FPS
1% low framerate : 42.4 FPS
06-07-2020, 21:05:43 7daystodie.exe benchmark completed, 92788 frames rendered in 1173.250 s
Average framerate : 79.0 FPS
Minimum framerate : 16.8 FPS
Maximum framerate : 102.5 FPS
1% low framerate : 23.9 FPS