All the parameters seem fine on your computer. I managed to fix my problem with uninstalling a few windows updates and reinstalling manually newest drivers for everything i could find (i do not know which one did it because i tried like 50 things). I...
Could you check task manager disk usage while playing? I have been experiencing a similar problem last week. The disk usage is 99% and transfer rates are very low (100% is 1 MB/s at times). When game starts loading content frame drops to unacceptable...