Is it faster to move files between media in large pieces (i.e. many files and folders within an archive) or move them file-by-file? Is there a significant difference, considering that the file transfer completes with no errors?
If contents and size are equal, then transferring one file should be faster due to only having one header/index entry to deal with. The setup and tear-down overhead of many files can add significant time to the transfers.
See this SU question for more info: Why does copying the same amount of data take longer if spread across many separate files?