[janovrom]

Thanks for shedding some light on this :) As you said, it's a specific scenario and I don't consider it an issue. It's just that those parts are there 50 times, so I thought that instancing would be worth a shot. The scene by itself has around 10m triangles, multiply by 4 for each window and of course it won't be 60 fps (but 20-30 is pretty solid). 
And of course, this is when the whole model is in view, with no frustum and occlusion culling.

But for the next version I have added a task to provide a new SceneNode object that will take DXMesh and InstancesData so it will be able to render instances data without MeshGeometry3D object (but still only using standard material).

This seems very cool. Looking forward to it.