Drop shadows down 1 level

Because CA lied about it being "future proofed" when they released it (it ran like ♥♥♥♥ for people when it released too on top range PC's) and it does actually just run badly. I can run Warhammer 2 easier than I can Attila, and all the games since Rome 2 are on the same engine as well by the way. Nothing you can do really. My advice though is never take what CA says at face value when it comes to the specifications needed or anything.

Clean the dust of your PC, and reapply the silicone grease on CPU and GPU.

most probably it's not running with multi thread. My pc was 9900x with 4070 and lagged like crazy, but when I change the seetings via text file, it runs like silk

Also changing core affinity from my all 16 cores to 0, 2, 4 and so on in task manager helped me to fix every lag and fps drop.

Yep, Homer is right on this one, it's the core affinity that fixed it for me as well.