send_bw test between QSFP ports on Dual Port Adapter

Hello Mellanox,

I have ConnectX-3 QSFP Dual Port CX354A Adapter with Windows 7 x64 Pro on PC, I would like to make throughput test between QSFP ports. For this connected 1m fiber cable between ports and set CX354A in Ethernet mode in Device Manager. I also manualy set different IP addresses for 2 Ethernet adapters with the same IP mask:





I tried make tcp iperf3 test, but I had only 12 Gbit/s instead of 40 Gbit/s. In your documentation where ib_send_bw utility was recommended for testing the performance.

How make test with ib_send_bw between two Ethernet interfaces on one PC?

For example: to set interface in iperf3 I can choose with key -B: iperf3 -B

Thank you.

With Best Wishes,


Hi Dmitri,

For testing tcp performance in Windows we recommend using nttcp tool, From the command line kindly run the NTttcp test and provide the output, the NTttcp tool is provided by Microsoft to test the network performance.

For example:

Server side: ntttcp.exe -s -m 8,*, -l 128k -a 2 -t 30

Client side: ntttcp.exe -r -m 8,*, -l 128k -a 2 -t 30

For your reference kindly see the download and explanation link:

Please let me know about the results.