unreal cloud?

How to get the most realistic clouds ?

I've tried different variations (textures and settings) but don`t get good results - part of the clouds are too dark in day time  (unrealistic).

example here (P3v2.1,ORBX,REX4,ASA2012)

Options - HDR_OFF, Volumetric fog ON,Detailed Clouds and so on

When I look out the window