это если всё по умолчанию в iperf

-R для download (если на клиенте запускать)

-P4 - в 4 потока

ok

[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-30.00  sec  39.3 MBytes  11.0 Mbits/sec    0             sender
[  4]   0.00-30.00  sec  39.0 MBytes  10.9 Mbits/sec                  receiver
[  6]   0.00-30.00  sec  38.4 MBytes  10.7 Mbits/sec    0             sender
[  6]   0.00-30.00  sec  38.0 MBytes  10.6 Mbits/sec                  receiver
[  8]   0.00-30.00  sec  41.0 MBytes  11.5 Mbits/sec    0             sender
[  8]   0.00-30.00  sec  40.1 MBytes  11.2 Mbits/sec                  receiver
[ 10]   0.00-30.00  sec  41.0 MBytes  11.5 Mbits/sec    0             sender
[ 10]   0.00-30.00  sec  40.2 MBytes  11.2 Mbits/sec                  receiver
[SUM]   0.00-30.00  sec   160 MBytes  44.7 Mbits/sec    0             sender
[SUM]   0.00-30.00  sec   157 MBytes  44.0 Mbits/sec                  receiver

iperf Done.

так проблема не в получении клиентом

проблема в отсылке от клиента в сторону сервера

видно как целыми секундами клиент ничего не передаёт

[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-30.00  sec  3.12 MBytes   874 Kbits/sec                  sender
[  4]   0.00-30.00  sec  2.96 MBytes   829 Kbits/sec                  receiver
[  6]   0.00-30.00  sec  3.00 MBytes   839 Kbits/sec                  sender
[  6]   0.00-30.00  sec  2.88 MBytes   804 Kbits/sec                  receiver
[  8]   0.00-30.00  sec  2.50 MBytes   699 Kbits/sec                  sender
[  8]   0.00-30.00  sec  2.34 MBytes   653 Kbits/sec                  receiver
[ 10]   0.00-30.00  sec  3.00 MBytes   839 Kbits/sec                  sender
[ 10]   0.00-30.00  sec  2.96 MBytes   828 Kbits/sec                  receiver
[SUM]   0.00-30.00  sec  11.6 MBytes  3.25 Mbits/sec                  sender
[SUM]   0.00-30.00  sec  11.1 MBytes  3.11 Mbits/sec                  receiver

iperf Done.

C:\Users\Administrator\Desktop\iperf-3.1.3-win64>iperf3  -P4 -c 192.168.0.1 -p2222 -t 30
Connecting to host 192.168.0.1, port 2222
[  4] local 192.168.0.3 port 49784 connected to 192.168.0.1 port 2222
[  6] local 192.168.0.3 port 49785 connected to 192.168.0.1 port 2222
[  8] local 192.168.0.3 port 49786 connected to 192.168.0.1 port 2222
[ 10] local 192.168.0.3 port 49787 connected to 192.168.0.1 port 2222
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   256 KBytes  2.10 Mbits/sec
[  6]   0.00-1.00   sec   256 KBytes  2.10 Mbits/sec
[  8]   0.00-1.00   sec   256 KBytes  2.10 Mbits/sec
[ 10]   0.00-1.00   sec   256 KBytes  2.10 Mbits/sec
[SUM]   0.00-1.00   sec  1.00 MBytes  8.39 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   1.00-2.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   1.00-2.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   1.00-2.00   sec   128 KBytes  1.05 Mbits/sec
[ 10]   1.00-2.00   sec   128 KBytes  1.05 Mbits/sec
[SUM]   1.00-2.00   sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   2.00-3.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   2.00-3.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   2.00-3.00   sec   128 KBytes  1.05 Mbits/sec
[ 10]   2.00-3.00   sec  0.00 Bytes  0.00 bits/sec
[SUM]   2.00-3.00   sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   3.00-4.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   3.00-4.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   3.00-4.00   sec   128 KBytes  1.05 Mbits/sec
[ 10]   3.00-4.00   sec   128 KBytes  1.05 Mbits/sec
[SUM]   3.00-4.00   sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   4.00-5.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   4.00-5.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   4.00-5.00   sec  0.00 Bytes  0.00 bits/sec
[ 10]   4.00-5.00   sec   128 KBytes  1.05 Mbits/sec
[SUM]   4.00-5.00   sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   5.00-6.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   5.00-6.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   5.00-6.00   sec  0.00 Bytes  0.00 bits/sec
[ 10]   5.00-6.00   sec  0.00 Bytes  0.00 bits/sec
[SUM]   5.00-6.00   sec   256 KBytes  2.10 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   6.00-7.00   sec   256 KBytes  2.10 Mbits/sec
[  6]   6.00-7.00   sec   256 KBytes  2.10 Mbits/sec
[  8]   6.00-7.00   sec  0.00 Bytes  0.00 bits/sec
[ 10]   6.00-7.00   sec  0.00 Bytes  0.00 bits/sec
[SUM]   6.00-7.00   sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   7.00-8.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   7.00-8.00   sec  0.00 Bytes  0.00 bits/sec
[  8]   7.00-8.00   sec  0.00 Bytes  0.00 bits/sec
[ 10]   7.00-8.00   sec   128 KBytes  1.05 Mbits/sec
[SUM]   7.00-8.00   sec   256 KBytes  2.10 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   8.00-9.00   sec   128 KBytes  1.05 Mbits/sec
[  6]   8.00-9.00   sec   128 KBytes  1.05 Mbits/sec
[  8]   8.00-9.00   sec  0.00 Bytes  0.00 bits/sec
[ 10]   8.00-9.00   sec   128 KBytes  1.05 Mbits/sec
[SUM]   8.00-9.00   sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]   9.00-10.00  sec   128 KBytes  1.05 Mbits/sec
[  6]   9.00-10.00  sec   256 KBytes  2.10 Mbits/sec
[  8]   9.00-10.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]   9.00-10.00  sec   256 KBytes  2.10 Mbits/sec
[SUM]   9.00-10.00  sec   640 KBytes  5.24 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  10.00-11.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  10.00-11.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  10.00-11.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  10.00-11.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  10.00-11.00  sec   256 KBytes  2.10 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  11.00-12.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  11.00-12.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  11.00-12.00  sec  0.00 Bytes  0.00 bits/sec

[ 10]  11.00-12.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  11.00-12.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  12.00-13.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  12.00-13.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  12.00-13.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  12.00-13.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  12.00-13.00  sec   128 KBytes  1.05 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  13.00-14.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  13.00-14.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  13.00-14.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  13.00-14.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  13.00-14.00  sec   128 KBytes  1.05 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  14.00-15.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  14.00-15.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  14.00-15.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  14.00-15.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  14.00-15.00  sec   128 KBytes  1.05 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  15.00-16.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  15.00-16.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  15.00-16.00  sec   256 KBytes  2.10 Mbits/sec
[ 10]  15.00-16.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  15.00-16.00  sec   256 KBytes  2.10 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  16.00-17.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  16.00-17.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  16.00-17.00  sec   256 KBytes  2.10 Mbits/sec
[ 10]  16.00-17.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  16.00-17.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  17.00-18.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  17.00-18.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  17.00-18.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  17.00-18.00  sec   256 KBytes  2.09 Mbits/sec
[SUM]  17.00-18.00  sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  18.00-19.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  18.00-19.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  18.00-19.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  18.00-19.00  sec   256 KBytes  2.10 Mbits/sec
[SUM]  18.00-19.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  19.00-20.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  19.00-20.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  19.00-20.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  19.00-20.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  19.00-20.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  20.00-21.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  20.00-21.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  20.00-21.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  20.00-21.00  sec   256 KBytes  2.09 Mbits/sec
[SUM]  20.00-21.00  sec   384 KBytes  3.14 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  21.00-22.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  21.00-22.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  21.00-22.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  21.00-22.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  21.00-22.00  sec   384 KBytes  3.16 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  22.00-23.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  22.00-23.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  22.00-23.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  22.00-23.00  sec   256 KBytes  2.10 Mbits/sec
[SUM]  22.00-23.00  sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  23.00-24.00  sec   256 KBytes  2.10 Mbits/sec
[  6]  23.00-24.00  sec  0.00 Bytes  0.00 bits/sec
[  8]  23.00-24.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  23.00-24.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  23.00-24.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  24.00-25.00  sec   128 KBytes  1.05 Mbits/sec
[  6]  24.00-25.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  24.00-25.00  sec   128 KBytes  1.05 Mbits/sec

[ 10]  24.00-25.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  24.00-25.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  25.00-26.00  sec   256 KBytes  2.10 Mbits/sec
[  6]  25.00-26.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  25.00-26.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  25.00-26.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  25.00-26.00  sec   512 KBytes  4.19 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  26.00-27.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  26.00-27.00  sec   256 KBytes  2.10 Mbits/sec
[  8]  26.00-27.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  26.00-27.00  sec  0.00 Bytes  0.00 bits/sec
[SUM]  26.00-27.00  sec   384 KBytes  3.14 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  27.00-28.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  27.00-28.00  sec   128 KBytes  1.05 Mbits/sec
[  8]  27.00-28.00  sec   128 KBytes  1.05 Mbits/sec
[ 10]  27.00-28.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  27.00-28.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  28.00-29.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  28.00-29.00  sec   256 KBytes  2.10 Mbits/sec
[  8]  28.00-29.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  28.00-29.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  28.00-29.00  sec   384 KBytes  3.14 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[  4]  29.00-30.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  29.00-30.00  sec   256 KBytes  2.10 Mbits/sec
[  8]  29.00-30.00  sec  0.00 Bytes  0.00 bits/sec
[ 10]  29.00-30.00  sec   128 KBytes  1.05 Mbits/sec
[SUM]  29.00-30.00  sec   384 KBytes  3.15 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-30.00  sec  3.12 MBytes   874 Kbits/sec                  sender
[  4]   0.00-30.00  sec  2.96 MBytes   829 Kbits/sec                  receiver
[  6]   0.00-30.00  sec  3.00 MBytes   839 Kbits/sec                  sender
[  6]   0.00-30.00  sec  2.88 MBytes   804 Kbits/sec                  receiver
[  8]   0.00-30.00  sec  2.50 MBytes   699 Kbits/sec                  sender
[  8]   0.00-30.00  sec  2.34 MBytes   653 Kbits/sec                  receiver
[ 10]   0.00-30.00  sec  3.00 MBytes   839 Kbits/sec                  sender
[ 10]   0.00-30.00  sec  2.96 MBytes   828 Kbits/sec                  receiver
[SUM]   0.00-30.00  sec  11.6 MBytes  3.25 Mbits/sec                  sender
[SUM]   0.00-30.00  sec  11.1 MBytes  3.11 Mbits/sec                  receiver

iperf Done.

полный лог

[  4]  16.00-17.00  sec  0.00 Bytes  0.00 bits/sec
[  6]  16.00-17.00  sec  0.00 Bytes  0.00 bits/sec

вот например

тот же самый тест (без -R) то есть от клиента к серверу на внешний айпи (то есть не через туннель)
[SUM]   0.00-10.00  sec  61.4 MBytes  51.5 Mbits/sec                  sender
[SUM]   0.00-10.00  sec  61.4 MBytes  51.5 Mbits/sec                  receiver

здорово если такие портянки куда-нибудь на пастбин будут складываться

читать невозможно

хорошо, я не очень часто с этим дело имею, поэтому некультурный еще :), но я учусь :)