What version AutoCAD/CADmep?

I know 2017 has been a rough year.... If you have access to a previous one, try it just to see if it has an affect.

Also, you may want to turn down the number of facets being displayed, get rid of the hidden line features, etcetera. Its all in the display area of the user settings\takeoff page. Also, make sure you aren't saving graphics with drawing. Shouldn't have an affect, but I suppose it could.

Do you have a lot of converted 3D models in these plots?