AA, texture loading, resolution, character movement(such as the actions of a model, not the direction AI takes). pretty much anything that you see, such as game models and anything the relates to scale of the picture and smoothness of the edging is handled by the GPU. Most times the AI control is done by the CPU side to balance the load. im not too technical with exactly which is handled by what but it also is different from program to program, its all dependant on the way the programmers made the game.