Well, in fact optimization of two different hardware components from two different manufacturers put in same MD will always cause some "total power" loss... some process and data flows will be slower because components must compile data between themselves, that is caused by different architectures and data arrangement. So that means the optimization to all CPUs and GPUs manufacturers for one game is really hard to do. Its really hard to say how much effectively two different components working together. PC assembling is damn science and many guys who complaining on bad game optimization and have CPU from AMD and GPU from Nvidia are trapped by their own decision. Remember you can only fully optimize any software with only one kind of hardware components, and in fact its more about hardware setup than about software optimization... And have on mind INTEL(+Nvidia) and AMD are rivals their products will never be fully compatible thats the intention...