AMD switchable graphic driver is horrible. My friend once purchase laptop with this function, then only few years, AMD relegated HD4000 mobility series to so called LEGACY driver without fixing existing issue with switchable graphic. Even Nvidia Optimus support for windows is better. BTW, both AMD and NVIDIA switchable graphic support for linux is equivalently horrible.
Beside, these APU has one fatal flaw.
If the CPU base frequency is 3.7Ghz (turbo 3.9ghz), whenever there is slight IGPU activity, the CPU frequency will be throttled to 3.0ghz regardless of temperature.
AMD marketing team tries to play down the problem by saying it is part of design, balanced thermal usage between gpu/cpu.
Yet, AMD keeps on marketing the total GFLOPS of 800+ when using both CPU and IGPU fully. Source : http://www.zdnet.com/computex-2014-amd-announces-kaveri-mobile-chips-challenges-intel-7000030197/
Assuming if a program utilises both cpu and igpu, that marketing claim of 800+ GFLOPS can never be achieved due to the throttling issues.
I admit AMD has the best marketing team, but worst engineering team.