I've tested using iperf the file server to the windows server and I've
got 400Mbits. The other linux server got 600Mbits. Also I've tested
iperf between windows server and another same type supermicro with
hyper-v and got around 650Mbits.
I've tested samba speed from windows to other linux server. It gives
90MB/s at read from that server and 70MB/s of write. 2 times of the file
server with problem.
Using smbclient:
From file server to other liux box - 48MB/s
from othe linux box to file server - 65MB/s
This is what I could test more.