Single nvlink bridge between PCIE A100 40g


I got a single bridge connecting 2 A100 40gbs in a supermicro AS -4125GS-TNRT across the GPUs’ first nvlink slot, I have the cuda toolkit, cuda 12.3, and 545 driver installed.

But nvidia-smi topo and nvlink -s both show the absence of nvlink

Is this because I’m using only 1 bridge instead of 3? Or is there another issue.

Bridge is seated fully as per the image.


Hi, I was looking for the answer to this question seperately and found this while I was looking. Since I don’t see any replies here I thought I’d just let you know that it is not supported. the only supported arrangement appears to be 3 bridges between 2 cards.
Screenshot 2024-03-28 115604

source a100 80GB product brief:

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Thanks for the reply, I also found a dell rack information sheet that says you need all 3 bridges.

Quite unfortunate