thief is on ue3 and even the developers said that it will not make a huge difference because of that. the difference is noticeable when the api gets in the engine like the oxide engine, frostbite 3, and the other one i can't remember right now. oxide will release a tech demo of nitrus engine in the future acording a video on amd's channel. there are a couple of interesting videos about this nitrus engine oxide guy talking about mantle oxide main code developer talking about mantle real-time directx vs mantle on nitrus engine. i have to say, i'm impressed with the results of mantle. and the cpu on all videos is a fx8350 downclocked to 2.0ghz!