Also, check the views you are placing and see how many elements are on that view.
I once had to work on a 3rd party project that had a worksheet with more than 10000 lines/arcs on it due to lots of horrible exploded DWG stuff being pasted around with lots of duplicate items.
The view worked well enough in worksheet, but the placed drawing brought ArchiCAD to a crawl.
Erwin Edel, Project Lead, Leloup Architectenwww.leloup.nl
ArchiCAD 9-26NED FULL
Windows 10 Pro
Adobe Design Premium CS5