I have 9T to transfer for an indie feature project. The data is on 3 USB3 drives and I am trying to transfer to a 4 Disk RAID5 box and the finder is telling me 3 Days to transfer! I am only getting 30-40 MBS transfer speed. I tried copying a single folder to a USB3 SSD and got 100+ MBS, not great, but at least I know the originals can be read at over 100MBS. I then tried transferring from the SSD (the SSD's are connected with hi speed USB controllers that I have tested to almost 500MBS) to my RAID, and got 200MBS. Pretty respectable. I then reconnect the originals to the RAID and still only get 40MBS. This is all on the same USB3 Bus. Tried it on both a Mac Pro (yes I know the USB bus sucks) and a Macbook Pro, same results. Can anyone explain why if I can read the disks at 100 plus, and my RAID is capable of writing 200+ I can only get 40MBS?