Frame drop with foliage tool

Hi,

I wanted to use the foliage tool to place a higher amount of my rocks on a landscape. The problem now is, that the frame rate drops realy bad when the base mesh is loaded. If the LOD is displayed everything is okay.

First i thought that the base mesh needs to much memory or something, but i placed ~15 Stone by hand, the framerate stays at ~40fps, if I place the same amount with the foliage tool it drops to ~13 fps.

This happens with 4.9 and 4.10