With prefs. set to not show thumbnails in the Recent Files list, this works OK for .dgn files, but still shows them for .dwg files. Is this WAD?
It’s a WAD. Turn On/OFF Thumbnails only addresses DGN files.
Thumbnails for DWG files between older (2010 or earlier) and newer versions are handled differently. Also other factors like, how the DWG file was saved, with or without thumbnails etc.
Really. Well that does seem rather odd. So if you work in .dwg files most of the time then you wont see the performance increase!! Why isn't this for all file types?