I’m starting to think that mys slow down could be a bug related with normal map textures or material problem. If I save small taking out everything the mesh is not the problem and Rhino is pretty fast.
3DM files
V1 past and copy slow (includes a normal map texture)
V2 past and copy fast (does not include a normal map texture)
PolyReductionV1.3dm (450.4 KB)
PolyReductionV2.3dm (410.5 KB)