Selection seems to work in wierd ways. I have a 3D File with ~4.000.000 Tris and ~120.000 Objects. The file results from a CAD software and needs to be further processed.
My idea was splitting the File in smaller parts because opening it takes minutes and the viewport is very laggy. But the real problem is that simple things like selecting parts of something take ages (for larger areas minues) and give not the expected results. (100% one CPU-core the others idling - The machine isn't the problem)
Edit: Selectable parts seem to be consitend till i moving the selectet parts to a different layer (takes minutes to finish). After that other parts become selectable.