hierarchical Instanced static mesh component - Performance issues ?

Hey guys,

i made a topic some days ago regarding HISMC´s and now i am running into some performance issues. See the two pics below… In the first picture you can see some buildings (not finished yet, they are procedurally generated), each of them has 140 meshes (hismc) . in the second picture you can see one big building with about 8000 instances…

My problem is, that the first version is way slower than the huge building. I basically wanna use a lot of instancing because my building algorithm is based on using instances. That means i want to build a city and each house is generated with the blueprint.

Any ideas how i can get rid of the performance issues? i really wonder why i can use about 8000 instances with no problem in one blueprint, but when i use 5 blueprints with each 140 meshes it seems to make a problem.