I do not expect a 5K iMac to have any more powerful GPU btw, experience shows that no substantial horsepower is needed for common desktop composing tasks. Memory bandwidth is more important!
This, no other mobile GPU is suitable for 5K display at this point. The new 900 series from Nvidia puts most AMD cards to shame in terms of performance per watt. There is no reason to go AMD at this point especially for machine like iMac. They need to keep it cool as possible and the best way to do it is by using less power.It has to be a 980M, nothing else will be acceptable.
AMD tonga R9 m295X. I guess they'll want to leverage OpenCL performance with 4k content on Adobe CC and FCPX.
To be honest if Apple did jump ship to AMD for the next refresh, I think I'd give it a miss until they re-adopt NVidia; there's just too many issues with AMD mobile cards and I don't want to go back there with heat etc as well.
I'm not sure what AMD have planned for the future of their mobile graphics line, but I'm sure that it would have to be something pretty substantial in order to compete with NVIDIA's offerings.
What issues? Honest question, it's the first time I hear there are major issues with AMD mobile GPUs (recently, at least).
Those are desktop graphics cards. It's unlikely that Apple will put desktop class graphics in the iMacs since they've never done it before, and the heat would be too much. Power consumption would also go up.
I wouldn't count out a custom Tonga-based part along the lines of the Dx00s in the Mac Pro either.AMD tonga R9 m295X. I guess they'll want to leverage OpenCL performance with 4k content on Adobe CC and FCPX.
i really hope for the 970M and BTO 980M
980M 2048 CUDA cores with 8 Gb vRAM
Nvidias mobile division has been slowly but surely catching up with its desktop counterparts as the generations and architectures progress. According to a slide by Nvidia, the 980 and 980M are only ~10% apart.
Those are desktop graphics cards. It's unlikely that Apple will put desktop class graphics in the iMacs since they've never done it before, and the heat would be too much. Power consumption would also go up.