There's a mesh scale option under the highpoly and lowpoly tabs. Try changing it from 1 to 10 or even 100. You'll have to do this for both the highpoly and lowpoly meshes.
I dont know whether 3DSMax has the same thing, but Maya allows you to upload meshes onto the VGA via a plugin called (IIRC) Alembic, which makes handling highpolys waaaaaayyyy more manageable. You still have to import them the normal way, but then you transfer the load onto the GPU and it gets way smoother. A little…