Sorry but i can't see AMD just going bang and taking 50% straight away, I think it's the other way around Intel & Nvidia still have plenty of tricks up there sleeves.
Remember it's AMD that has to come out with a game changing CPU & GPU, Intel & Nvidia doesn't well at least not at the moment anyway.
IMO Intel & Nvidia are just sitting back and waiting for AMD and then they will go from there. Which there allow to do.