about 2 years ago - AndrewT - Direct link
There have been performance issues with large empires since the game was released, IME. Perhaps it is a little worse, or rather starts a little earlier, with this patch and the extra features and DLCs.

You could try deleting the Documents/Paradox Interactive/CK3 folders (except any valued saved games.

Then Right click on ck3.exe , properties, compatibility. Tick "disable fullScreen optimisations" untick every other box in that dialog, Apply and exit.

Then in the launcher Game Settings menu, select fullScreen display mode, Vsync off, refresh rate 60.

Then unload GeForce Experience if running.

Is that any better?  
about 2 years ago - AndrewT - Direct link
Does this thread seem to apply to your problem?

forum.paradoxplaza.com

Constant Stutter

I saw a few other posts with the same issue, so i figured id post my own to hopefully get it fixed ASAP, as it is very debilitating. Every few settings the game stutters really bad, and this is a new issue that popped up after the friends or foes... forum.paradoxplaza.com forum.paradoxplaza.com