Issue with Mellanox Connectx-3 MCX341-A NIC not being picked up by mobo

Khiman

New Member
Jun 2, 2020
2
0
1
Hello, I just bought a few of these from the popular eBay listingthat seems to have a huge quantity. I'm trying to install one of them in a Windows 10 gaming rig, which has an i9-9900k on an Aorus Master Z390.
I can't get any of the cards I bought (3) to be recognized by the computer in any way. I installed the corresponding drivers but the PCI device isn't even showing up in the bios, it just says "not connected" on the corresponding pci slot. However, the PCI card is powered correctly, I see the SFP+ leds blinking, and the link is shown as active 10Gbps on my router.

I tried putting a jumper on the card to put it in flash mode, same result apart from the fact that in this mode the card just has a continuous green light.

So, is there anything I should have done prior to just putting it in the mobo ?
Is there a compatibility issue I'm not aware of here?

Before you ask, the motherboard pci slots are supposed to be in order :
- 16x
- 8x
-4x

If anything is in the second slot, the first one goes down to 8x as well, and the last one is on 2x when the shared m2 port is in use, which it is not in my build. I tried putting the card in all 3 pci slots, to no avail.
 

RobstarUSA

Active Member
Sep 15, 2016
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I had a similar issue on my Crosshair VI /3900x combo.

I ONLY tried in the 3rd slot. The third slot is shared with 3 pcie- x1 devices. I eventually solved it but reconfiguring the PCI-E lanes in the BIOS & hard powering off & back on.

Are there pcie- lane configuration options in the bios?
 

Khiman

New Member
Jun 2, 2020
2
0
1
I had a similar issue on my Crosshair VI /3900x combo.

I ONLY tried in the 3rd slot. The third slot is shared with 3 pcie- x1 devices. I eventually solved it but reconfiguring the PCI-E lanes in the BIOS & hard powering off & back on.

Are there pcie- lane configuration options in the bios?
Sadly, no. I only have an option to select whether it should use UEFI or Legacy to boot PCI devices other than GPUs, and an information panel that displays the current status of pcie slots like the speed it's running at and if anything is detected in it or not.

I only see my GPU in there running on 3.0 16x in the top slot, and nothing with the mlx card.

I also tried different combinations of hard and warm reboots, nothing worked. I know some non compliant pci devices take too long to be picked up by the bios so they never end up in the ACPI table in time for windows to pick them up. Usually in this case a warm reboot is enough for the bios to add the missing entry in the acpi table and the issue is gone, but in my case that does not seem to be the issue.
 

necr

Member
Dec 27, 2017
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Thanks for the feedback, now I know that Gigabyte leaves you SOL with PCIe configuration. Easiest way - find another PC to test it on. I would expect something early on from a working card - legacy Flexboot (iPXE) or beta UEFI could be on it, also I wouldn’t trust consumer BIOS to provide you with the reliable information.