Mellanox 40gb only connecting at 10gb

This is my first time getting into Mellanox, so as a newbie I expected a few issues along the way. The good news is my controllers are working well at 10gbps, but my Windows machines are only connecting at 10gbps (full duplex) in ethernet mode directly connected, no switch.

I am using the Mellanox MCX353A-FCBT ConnectX-3 cards in both systems. Drivers have been updated on both cards to 5.50.14688.0. I am using the MC2206130-003 cable from It states that it “supports 10G/40Gigabit Ethernet.” It can be found here: Mellanox MC2206130-003 40G QSFP+ DAC Cable

New Hardware/systems:

System 1: Threadripper 1950x, 64gb RAM, x399 mobo, Samsung 970 Evo Plus M.2, Windows 10 . Mellanox is installed in a PCIex 16 slot.

System 2: Xeon W2102m 16gb RAM, Supermicro X11SRA-F mobo, Samsung 970 Evo Plus M.2. Windows Server 2019. Mellanox is installed in a PCIe x16 slot.

It is quite possible I am missing something obvious, but my normal internet searches have yielded nothing. I read there are some tuning tools for Linux, but can not find anything for Windows based systems.

Using the MST tools, I am able to see that I have a Device ID of 4099 (ConnectX-3) and a PSID of MT_1100120019.

It appears that my current firmware version (2.42.5000) is the latest offered.

Thanks in advance!

Hello David,

I do not see Windows 7 as supported.




Many thanks,



Hi Stephen.

I edited my original post to reflect my error. I am on Windows 10 Education (Enterprise basically). I have been running Windows 7 so long, I typed it by accident.

I will add the following information, hoping it may be pertinent:

Operational Info for Port# 1:-----------------------------State : ActivePhysical State : ETH_AN_FSM_AN_GOODSpeed : 10 GbpsFEC : No FECLoopback Mode : No LoopbackSupported speeds : 0x1000 ( CR-10G )

Bus:65 Device:0 Function:0TroubleShoot Info Port# 1--------------------------Status Opcode : 0Group Opcode : 0Message : No issues detectedBus:65 Device:0 Function:0Operational Info for Port# 2:-----------------------------State : DisabledPhysical State : ETH_AN_FSM_ENABLESpeed : UnknownFEC : No FECLoopback Mode : No LoopbackSupported speeds : 0x1000 ( CR-10G )

Bus:65 Device:0 Function:0

TroubleShoot Info Port# 2--------------------------Status Opcode : 1Group Opcode : 0Message : The port is closed by command . Please check that the interface is enabled.

I have ordered a different cable, hoping this may be the issue, as I read on the mellanox supported cables list that I had bought a FDR10 cable, instead of a 40gb cable as listed on the support .pdf. However, I am also reading that a FDR10 cable should be ethernet compatible at 40gb.

Your help is GREATLY appreciated.

As it turns out, it was a cable issue. While the MC2206130-003 says it supports 40gb ethernet, it evidently does not, at least with my hardware. Buying the MC2210130-001 cable did the trick.