haha, thank you :D
actually the cycles renders are very grainy, you just don't see it because theyre scaled down to 40% :D
they ran 10000 samples on my machine which i put 2x 1070 in for this experiment. took as long as the corona renders (5k 8hrs).
but still very grainy. I tried a lot of things they are suggesting on the blender forums; like clamping etc.. but well - the grain persists.
I suspect the fact cycles is missing all kind of lightcaching, but for that i am not technical enough - so it is just vague speculation.
yes, maybe i walk over to the blenderartist forum :D curious
L