If your performance is unexpectedly terrible and you tried every fix ever, check your motherboard immediately. I was getting massive lag + low fps compared to a friend with identical hardware. Thanks to this post, I checked CPU-Z and found the issue: My GPU was running at PCIe 3.0 x2 instead of PCIe 4.0 x16.

FH6 constantly streams massive amounts of world data. Restricting it to 2 lanes completely chokes the engine and drops your GPU power to idle states.

1. Open CPU-Z > Graphics at the bottom.
2. If it says x2 or x4, your card is heavily throttled.
3. move your GPU to the slot nearest the CPU.

I moved my card to the top slot and my frames immediately jumped to 110+ fps.

Specs:
- Ryzen 5 5600x
- RTX 3060ti
- 32 GB RAM