Please note that neither GGM2 nor GrinPro2 implement pow auto-switch for the upcoming hard-fork. Both will be replaced with fully open-source GGM3 tuned only for Cuckarood29 (AMD and nvidia). As the OpenCL code will be compiled on launch, it should be compatible with all AMD 8GB+ cards and all drivers.
When it comes to speed, it will be slower compared to closed Cd29 miners on nvidia hw and still the fastest on AMD (Cd29).