Why do people keep repeating this fallacy? The game definitely uses multiple cores, I've verified this myself, as have multiple review sites. Personally I think the game is fairly well optimized, with the exception of the PhysX component, which was basically "glued" onto the game. I have it turned off and I love PhysX. The PhysX quality in this game is subpar however, because it wasn't planned from the inception and was obviously rushed. PhysX is always best when the game is built with it in mind, but AC IV already uses Havok for Physics. But if I can run the game with all settings maxed (PhysX turned off) at 2560x1440 and achieve 60 FPS with regularity, then it's not badly optimized..