If it does this even in an empty scene id suggest trying to cleanup your computer a bit and comparing your computer specs to what c4d recommends to run the program.
If its a scene with objects and models in it, try display > level of detail > medium or low AND/OR Display>OpenGL.
this is not a slow system… its a 3970x + 128gb + nvme
also these slow viewport changes do not happen with other renderers
the scene is not particularly large.. it is 350mb
maybe this is caused by scripting tags, i’ll do a test on this later today.