Extremely slow USB to USB transfer

[Jingles]

Hi @mk01,

Sorry for the really late reply. I read through that site very quickly at work when you sent it but it didn't make much sense to me, and then Christmas got in the way! I have just read through it again and understand it better now but I don't think this is the same problem. I am not using a SATA/USB converter, my HDDs are portable USB drives. Do you have any other ideas? Or would it be worth trying flashing the SD card again?

Pete