Old question, though this solution is missing from the answers. You could use iperf to test the speed between two machines, since ‘iperf’ was designed to measure bandwidth.
on machine1 (host, this one will receive)
iperf -s -p 65000
on machine2 (client, this one will upload)
iperf -c [ip of server] -p 65000
Reverse the machines to test the other way (upload->download or vice versa).