Demystifing NVLink

[arcmos]

There are now some myths about NVLink circulating on the web. In addition, different and partly contradictory information can also be found on the manufacturer's pages.

Does it matter in which slot on the motherboard the NVLink connected graphics cards are? Somewhere I read that the graphics card in the NVLink network must be in slot 1. Can't imagine that's true though.

I would like the following setup:

A4000 + [A5000+A5000]

A4000 image only (slot 1*)
A5000 nvlink (slot 3*)
A5000 nvlink (Slot 5*)

* Slot assignment according to ASUS Pro WS WRX80E-SAGE SE WIFI

[Muhammed_Hamed]

Does it matter in which slot on the motherboard the NVLink connected graphics cards are? Somewhere I read that the graphics card in the NVLink network must be in slot 1. Can't imagine that's true though

Hello arcmos

Answer to your question is specific to each motherbaord(and sometimes CPU), as different motherboards/platforms will assign PCIe bandwidth in different ways
In your case here with ASUS Pro WS WRX80E-SAGE SE WIFI Motherboard, the answer is "no" as all PCIe slots are x16 PCIe Gen4 which is more than enough bandwidth for NVlink
Feel free to install the cards in any order you like

Role of thumb is that NVlink needs x8 PCIe Gen 3 as minimum bandwidth to work, so on most X570 and B550 Motherboards you cannot use this configuration you wrote above, because the third slot is usually x4 bandwidth and is shared with other devices.
This might be why you read in some places that NVlink needs to be in slot 1 and 2
And again this doesn't apply to your Motherboard, you can install 3 pairs of NVlinked A5000s + one GPU for Monitors .. it is such a good board

I hope you find this helpful, and if you have more questions let me know

Best,

Muhammed

[arcmos]

Good news.

Thanks Muhammed