Moving folders · How moving folders works
Will files be slower to open after I move them to the external drive?
Short answer: Possibly, depending on the drive. Moved files open at the speed of your fast drive and its connection: a good SSD on a fast port feels close to the built-in drive, while a hard disk or slow hub is noticeably slower. Move things you open occasionally.
Possibly a little, depending on the drive. Files open from wherever they physically are, so a moved file opens at the speed of your fast drive and its connection. A good SSD on a fast port feels close to the built-in drive for everyday work; a hard disk, a slow USB port or a hub makes it noticeably slower.
That's why it's best to move things you open occasionally — archives, finished projects, media libraries — and keep the folders you hammer all day on your Mac. Storage Studio can test your drive's speed to help you choose. See external drives.