Plutonium

I'm having a particular issue, the game is literally running at 1fps (no, it's not an specs issue, and yes I've already tried the solutions on the website). I've changed resolutions, capped framerate, Alt+Enter couple times, disabled full-screen optimisations, gave high priority on task manager, even reinstalled both Pluto and game. Nothing worked.
Both CPU and GPU are running at less than 20% and, weirdly, when I Alt+Tab the game it shows 60fps for a second and then it goes back to 1fps. Does anybody know what could be happening?