What is the caused to make single port 50Gbps only on ConnectX-6 Dx NIC?

Hi sir,

I’m using ConnectX-6 Dx under Windows Server 2022, with the QSFP28 cable connect between two ConnectX-6 Dx card, the performance of single port I got is only about 50Gbps,

NIC: MCX623106AC-CDAT (plug on PCIe gen4 x16 slot)
NIC FW: v22.35.1012
NIC Driver: vv3.10.50000
Cable: FS Q28-PC03 Passive Twinax Cable Network Cable 3M
OS: Windows Server 2022 Datacenter

I’d like to know if any settings need be set to get signle port with 100Gbps performance, or how I can resolve this problem?


Hi Jacky,

From your description, I am not sure what is your detail test steps. I agree with you that the test result 50Gbps is not acceptable.

So I think you can have a look at these 2 document links about the performance tuning at Windows.

Please help to go through all the steps/suggestions in the 2 documents above.
If the performance problem still exist, then send the detail test steps from your servers side and with the deteil command output. I will help to investigate.

Longran Wei

Hi longanw,

I got ~93Gbps after installing the driver with custom installation(with performance tool) and then execute the MlxNdPerf.exe, suppose the issue is resolved by the tool.

But when I execute the performance test on both ports at the same time, I only got ~80Gbps.