I've written a game engine that, for now, support only opengl. I've used many modern tecniques, just like deferred shading, tone mapping. instancing. I've tested the engine on a Radeon HD 5850 and on an HD 5450. I've noticed that after catalyst 10.11 (openGL 4.0.10317) the performances of the driver calls drops down of 2-4x times. What's happened?