I’ve seen this too. Finder is useless when copying a large amount of files -- especially small ones.
Used to work at the Apple store and it was incredible how a handful of customers dropped thousands of files onto the desktop which in turn brought Finder to its knees.
Probably generating thumbnails or indexing is my unscientific guess
Used to work at the Apple store and it was incredible how a handful of customers dropped thousands of files onto the desktop which in turn brought Finder to its knees.
Probably generating thumbnails or indexing is my unscientific guess