I have currently set up a home gigabit network which consists of a gigabit router and a few machines which all have gigabit network adapters. Connections are made through cat5.e cables from which the longest one is around 20m long.
First I tested through FTP where the transfer rates varied around 300Mbit/s which was pretty poor but could be limited by many factors so then I resorted to using a specified utility for the purpose. I got
iperf3 running on both machines and as suggested in other answers first I tried running loopback tests on both machines to see if the system itself is capable of handling the traffic and here are the results:
Obviously I don't know what I'm doing but I suppose that the loopback is not supposed to go through the NIC so if that's the case these results make sense and mean that my machines are both capable of handling the connection.
Next I proceed to going from 1 machine to the other and here are the results
Which is not as bad as some other questions around the web, but still 100 mbit is 100 mbit.
I'm interested in finding out what's causing this, how can I diagnose the problem further?