With a parity disk active (write corrections on), cache off, copying one TB of small files to a share over gigabit ethernet from a USB 3.0 drive I was getting 10-15MB/s... I paused the transfer, selected "Reconstruct Write" under Settings > Disk Settings > Tunable (md_write_method), went to Main > Spin Up disks, and resumed the transfer in Windows. It averages now at 35MB/s. I get the same speed differences from a USB drive directly in Unraid from Krusader. I have many more TB of data to transfer from unassigned SATA disks, this thread saved me a few days of wait! I'll come back to report my findings, thanks to all for sharing.