(In reply to Alex Deucher from comment #13)
> gears is not a good test for PRIME systems.  It basically tests how fast the
> driver can swap buffers.  With PRIME the dGPU rendered buffers ends up
> getting copied several times before getting to the IGP.

Dear Alex, 
Thank you for your reply.
Could you please tell me a test I can run to verify this issue? 
I tried also glmark2 and glxspheres64, none of which showing better results. 
Also when gaming this behaviour is observable.
Cheers,
Arthur