3D CAD/CAM is still CPU (and to a lesser extent memory) bound --- I do joinery, and my last attempt at a test joint for a project I'm still working up to was a 1" x 2" x 1" area (two 1" x 1" x 1" halves which mated) which took an entry-level CAM program some 18--20 minutes to calculate and made a ~140MB file including G-code toolpaths.... (really should have tracked memory usage....)