If you want further performance improvements, get the UI Performance mod, it fixes the stutter when you select anything from the UI such as the Diplomacy screen, Faction Screen, etc.
The engine is searching for files in a folder that has nothing in it, so it has to search the entire Warhammer 3 folder to find the files it needs to load the data. That's the stutter there... That's a simple fix CA could have done since Warhammer 1... It's always been an issue.
All the mod does is copy the files it searches for and paste it in the first folder it searches.