I have a similar issue too. When I try to enter the war(seize of war doesn't matter) or places like cities and villages my pc going crazy. I have tried low and high settings and that didn't matter also.
My Pc running on an Asus Tuf with :
Intel i7-8750h
NVIDIA GTX 1050Ti 4 GB
8 GB RAM
I hope the game will be more efficient for our systems as soon as possible.