Hi, When I get this kind of grainy results from Iray and it has run for quite some time like your render, I have found what works for me is to increase the lighting by a considerable amount (2x to 3x - keeping the same proportions) on all light sources. Then reset the tonemapping. You can change any of the parameters (EV etc.) to get the light back to the same level you have. I know I have only had this problem with scenes I wanted lit less. I can tell you that it usually works for me.

That is a very nice composition and use of reflections.

Jack