I really don't understand Solidrocks render settings, I use it mostly for test renders, because I can set it at draft and preview, etc it saves time. But I recently started looking at those optimize vray render settings using sample rate. When I look at the sample rate of Solid rocks its all red, from my understanding, it shows that it's actually oversampling my image which in turn would INCREASE render times, yet it doesn't; strange strange stranger.
It's funny how everyone follows the same path in terms of learning the art of archviz. I used to wonder the internet looking for the best AA filter for that particular scene, that's the time I used Alleso's tutorial's, then I went to Viscobel ( still do ) and now I remove AA because you really don't need it.