It's around 4 MB/s
edit: if i do the other way (copy file from the box to windows) its about 11+ MB/s
Now I attached my wifi stick and the file copy is ~9MB/s
and now I can play 4K HDR content properly
still don't know why my download speed (30 Mbit/s) is so slow on wired connection when my upload is ok (90+ Mbit/s)
maybe the driver has some bug ?