I made one test now and have a question.
Made a simple grass with about 5 grass objects and scatter it on a land. With 270 000 objects, memory consumption on rendering for 3ds max was 2,8 GB. With 110 000 objects (only distribution scale and threshold was changed) was 1,6 GB. I think its a big difference, why is that? Used same objects, same land, same scene, so dont know why is that.