There's some weird optimization bugs with the PC version. I had around 70 fps on a mix of high/ultra, but with the annoying stuttering you could see in the Quick look.
But after opening task manager and setting the core affinity on the FH3 process to not use core 0 and putting the priority to low (don't really know if the latter had an impact), I don't have any stutters. It's a workaround worth a try. Credits to pcgamingwiki and the guy/girl that actually discovered it for that one.
shabador's comments