"--repeating-payload: Use repeating pattern in payload, instead of random bytes. The same payload is used in iperf2 (ASCII ’0..9’ repeating). It might help to test and reveal problems in networking gear with hardware compression (including some WiFi access points), where iperf2 and iperf3 perform differently, just based on payload entropy."Aha, good old transparent compression cheat. Becomes "infinitely" fast when you send a stream of zeros.