Speed up rsync over lan or wan with this simple addition to your command.
-e "ssh -T -c aes128-ctr -o Compression=no -x"
Her we use the new command in a safe (dry run) example
rsync -avn --progress -e "ssh -T -c aes128-ctr -o Compression=no -x" source/ user@x.x.x.x:/destination