$ iperf -c remote -P4
...
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 284 MBytes 238 Mbits/sec
[ 3] 0.0-10.0 sec 278 MBytes 233 Mbits/sec
[ 6] 0.0-10.0 sec 275 MBytes 230 Mbits/sec
[ 5] 0.0-10.1 sec 259 MBytes 216 Mbits/sec
[SUM] 0.0-10.1 sec 1.07 GBytes 915 Mbits/sec
OK, that's working.