My book Studio II 6tb RAID 1 write speed < 5mbs

Many things can afftct transfer speed, The read/write speed of the actual computer drive, antivirus and antimalware software, drivers in the whole USB or firewire chain. If there are updated drivers from the hardware manufacturer for of the devices involved update them. I don’t know much about Macs but in Windows you would want to check out the BIOS for updates.

Joe