1. Doesn't look like there were runs of iperf over UDP and TCP, with simulated buffer sizes, so hard to know what the network connection is even capable of. 2.

1. Doesn't look like there were runs of iperf over UDP and TCP, with simulated buffer sizes, so hard to know what the network connection is even capable of. 2. Also, how reliable is the network connection? Maybe it fluctuates every minute in usable bandwidth due to congestion or jitter. VMs are subject to noisy neighbor issues. 3. It looks like the ciphers are different, which could of course affect throughput greatly if one is not hardware accelerated or if its CPU bound. Worth checking CPU and other system resource usage for differences. 4. You could try OpenVPN with encryption and/or compression disabled entirely in UDP mode for best possible performance IIRC. This, at least, you would expect to beat an SSH tunnel.