Hi,
I the last days I've made some research to find bottlenecks. I've scanned the profiler and finnaly I've found a command that stalls the CPU dropping down framerate. Here are the results. As you can see the rendering is 6 fps faster in the example scene. I've tested it using an ATI Radeon 5850 HD. This is only the beginning and a lot of things can be still made for improving performances.
BEFORE
FPS=27
RenderSceneTime=30ms
AFTER
FPS=33
RenderSceneTime=19ms