PS4 boasts an APU with features that current PC’s do not have access to. This will change in future, but since every PS4 will have a fixed set of features, those features on PS4 is more likely to be utilized.
What is an APU? It is a processor with integrated CPU and GPU, where the CPU and GPU share the same die. They are part of AMD’s vision for Heterogeneous Systems Architecture (HSA), formerly known as Fusion. The tools to make the most out of HSA systems is maturing, and it will take time before developers can get to grips with this.