Is this a new issue with the latest patch? I have the game for both PC and PS5 and act 3 runs just fine on both for me. I beat the game shortly after patch 3 came out. I have a mid low tier PC (RTX2080) and am able to play the game at 90fps at 1440p easily on act 3. There’s also barely any issue when I’ve loaded into act 3 on my PS5.