My server has never had performance issues and suddenly since the last wipe it randomly throttles down to 2-3 FPS. All plugins are working, all of them are updated, and I'm not getting any error in the server console. It just randomly goes below 100FPS all the way down, sits there for 20-30 seconds (avg, sometimes longer) then comes back up to 100+. 

Yea. I usually stay around 60 (give or take).  Sometimes drop to the 40s.   Today has been really bad.  Droping into the 10s for quite a while.  Total hook times on some of the larger plugins like stack modifier and truepve are usually 150 and 80 (respectively) near the end of the day.  Today, Stacks hit 900 and truepve 300 (so far).  No changes to configs/versions.  Usually reboot daily, but may have to make an unscheduled reboot to see if that helps.

I have my servers rebooting 2x a day (once at 1am and once at 1pm server time) and dont seem to have these issues and I have about 140 addons