Had a QNAP TS-669 Pro with two Gigabit NIC ports in the back. Plugged these into a single gigabit switch, which the computer used for file transfer testing was also plugged into.
Network settings in the management pages had a plethora of options to try. I decided to try some and see what the performance difference was when copy and pasting the same 1GB sized file into a directly accessed “//qnap/Public” . No optimizations/customizations had been done on the Qnap which had been reset to factory defaults. RAID 10 was used, although RAID 0 also gave the exact same results. 6 drives all SSD’s of 512GB (SATA III ).