Hi @litwinaa,
See if this tutorial on rendering jewelry in Rhino 7 helps with your set up.
Regarding the sluggish file, it could be render mesh density or something else file specific. Hardware is also a factor of course but 8GB of VRAM should be good for most scenes. Upload the file at Rhino - Upload to Support and put a link in the comments back to this thread as well as saying for BrianJ and I can take a look for you.