Rodney,
Are you saying that you are keeping files on your iDisk at .Mac and using an alias (Virtual Copy) stored on your hard disk to reference the file? If that is the case, then that may be a part of the slowness. Somebody that knows more about where Archicad saves files and writes the automatic backups may have a better idea of whether it is trying to write to the iDisk over the Internet or not. And if that is a good thing.
Also what version of Archicad are you using?
Ted Taylor
Atlanta, GA , USA
iMac (Retina 5K, 27", Late 2015)
3.3 GHz Intel Core i5 32GB
AMD Radeon R9 M395 2GB
OS10.14.2,
Latest Archicad 22