Thanks and congrats for the 1.9, the new sky system is great+++ (just to quote one thing among all!).
It seems that D5 doesn’t deal anymore with 8K texture. I mean most of the time 1 or 2K textures are enough for archviz, but in the specific case of a site area with a large aerial view texture file, this is a problem. It seems also at that scale maps are less responsive (AO, normal, color change…)
Here below you have a comparison between blender and D5, same mesh, same texture.
Resizing with reason all textures while importing is a good thing but maybe you could had an option for this case in the shaders type (like glass, alpha, you could have “extra large” or “site texture” or “High quality”).
You can download the file here with 2 versions of the mesh (high and less poly):
One small last thing on another topic; please, allow to sort the user library by letter or number; folders are listed randomly and it’s always a bit confusing to get straight to what you want.