Hi I have the same problem with Illustrator CS6. Overnight (no changes in the machine i am aware of) copying a set of drawings in an 325k file (just vector not embedded bitmap) to the clipboard takes 3 minutes instead of the usual 5 second, and the machine display a message
Filename @150% (CMYK preview)
or
Filename @150% (RGB preview)
This is win 10, all updated, 32 GB of RAM, reboot did not help, I did optimize window and i tried to cut and paste the artwork in a different file with no success
HELP !!!!!!!!