Pervasive and Repeatable FPS drop

Every 2-5 minutes my fps (capped at 145, steady at 144 constantly) will drop to 20-25 fps and stay there until I either reboot the game, or tab out and tab back in rapidly.

This only seems to occur in windowed fullscreen, haven't tried windowed mode in general because who plays like that? Playing in fullscreen appears to remove the problem entirely but somewhat invalidates my other 2 monitors for looking stuff up / trading / using discord etc.

I updated my gpu driver to be sure that wasn't the problem, currently on an RTX 2080 with driver build 456.38.

Windows 10 Pro build 19041.508

Intel i7 8700k OC'd to 4.8 Ghz

32gb ddr4 system RAM

Game installed on Samsung EVO 970 Plus NVME

Not sure if it's game side or something externally interfering due to the fact that quick tab out tab in fixes it and it doesn't occur in fullscreen but only programs im running in the background are POE overlay, discord, spotify, and chrome. Closing all of them doesn't stop the fps drop from occuring, and I wasn't having this issue in Harvest. The only thing that has changed is the update to Heist.