Hello,
I would be very interested about your solution if you found one...
I'm runung AC20 on my mid-2012 MacBook Pro all up to date with Sierra (15inch, NVIDIA GeForce GT 650M 1024 Mo, 1,5TB SSD, 16GB of RAM).
I have 3 level files
- Modules files for different kind of flats (6 hotlinks)
- Project file with the building and hot linked to the flats
- Project file with the building site, and for now just one building of 1,600 square meters...
Each time I want to touch something, I have to wait between 5-10 minutes. I have disabled all what you did. I tried the last AC20 (build 6005) update without any improvements.
In the past I had notice that since AC20, ArchiCAD didn't seem to be able anymore to handle wall layer under 1cm as for rain barrier... It made it unable to draw walls, but it's not my case right now...