The speed in rendering of all 3d models (not only Xfrog's) is not related to ecosystem and neither it is to polygons amount in ecosystem, but it is to bitmap textures. The more transmapped textures you have, the slower. This is why transmapped hair and transmapped vegetation are the slowest things to render. Also, the larger the bitmap textures, the slower. You have many options to reduce render time, I only mention some: 1) for background areas, don't populate with 3D models (which have hundreds if not thousands of alpha mapped leaves), populate with billboards instead (BTW, XfrogPlants libraries come with pre-rendered billboards images for all models) 2) rescale down texture sizes in Photoshop (beware of blurry textures in closeup - make tests) 3) consider replacing some transmapped leaves with polygon leaves (yes, as absurd as it may have sounded in the near past, with instanced distribution, a moderately sized polygon leaved model may render faster than a transmap leaved model when you reach or go beyond the 300-500 instances) 4) disable radiosity for the instanced objects (if you are rendering with radiosity of course) 5) disable texture antialiasing if you are using it (beware: the result may look worse than acceptable in some cases) 6) disable soft shadows if you are using them: the combination of soft shadows through transmapped leaves can be a real speed killer if you have hundreds of plants in a scene.