So here's the issue. I'm rendering my scene, with maybe 8 lights, and final gather on, nothing too complex. When I go to do a high quality render for the first time since opening the application, it renders in like, 1:58sec, but if I hit render with the same scene after it finishes, it will take like 18min to render.
When I look at my activity monitor, the first render has all cores running to maximum capacity for the most part. But for every following render, they are sporadically in between full and around 15% roughly.