External GPU for mac and upgrading from 5 to 7

Hey there! Does anyone use an external gpu with their mac for better performance? I’m looking to upgrade to Rhino 7 asap as i need to get better meshes from my models. I here that 7 is slower than 5.
I’m torn between getting a GPU or getting a PC. I’m also getting into blender so I’m going to need more power!!

THanks!

Moved to Mac Hardware category