Thank you guys for the help, the scene is well optimized in terms of displacement, textures resolution, no render elements (and this is quite frustating because it means I need to render out more than once), all trees, grass, bushes are all proxies.
The main issue is FP, it seems not optimized well yet to work with Corona and viceversa. Once I turn off all my FP everything is really smoth, IR as well, but otherwise it's just extremly slow, slower than Vray. :/ Any plan to improve this in the near future?
Thanks a lot.
Dan