In process of setup night scene I was stopped by huge amount of lights that slowe down my rendering. Direct lighting from this lights was too much noisy and it seems that nothing except unbelivable long rendertimes could remove it. I hope that I'll find a way to solve this problem.
As seen at the image most of light is ok in terms of noise, but light inside house is completely not! Waaay too noisy. It is no GI at all at this picture. Just direct light.