There are a number of reasons why it could be copying slowly...
-SCSI hardware settings (termination, parity, etc.). This might be why the drive isn't booting properly.
-Filesystem / MaxTransfer - what are the settings on the source and destination drives?
-Non-standard drivers. What hardware interface are the drives connected to? Maybe there's something in your startup-sequence or user-startup that loads in a better driver. The 2091 is one such board that benefits from this.
Suggest you cancel the copy (Ctrl+C) and find a solution for this first. Also, you should probably add the CLONE argument to your copy command to preserve filesystem protection bits, comments, and file dates.
