I have Raspberry Pi 3 B+ with IP 192.168.0.100 and Rock Pi 4 B with IP 192.168.0.200. Both in the same network connected to TP-Link 1043N V5 router. Both Pis have 1Gb Ethernet. However I am not able to use the whole bandwith even if it is not used elsewhere (only SSH on both to view tests).
What I get is:
Rock Pi receives data from Raspberry at 33.6MB/s and Raspberry receives data from Rock at 27.8MB/s.
I've made scripts to test that, both run either ways. Receive:
nc -l -p 3333 | pv -W > /dev/null
pv -B 1M /dev/zero | nc [other device's IP addr] 3333
What could be the problem here to achieve 1Gbps or 125MB/s?