Suggested cable to link two Sparks?

Accelerated Computing DGX Spark / GB10 User Forum DGX Spark / GB10
1

Could anyone suggest an appropriate cable to link two Sparks? They will sit on top of each other, so I’d prefer a short cable.

2

FS.com sells a 0.5m (2ft) NVIDIA/Mellanox MCP1650-V00AE30 that’s on the list of approved devices from NVIDIA.

Ref:

Which Cables to be used for ConnectX-7? - #2 by MvB

3

While waiting for my Mellanox cable — you can connect two Sparks over ethernet and have NCCL work just fine. It’s slow of course, but it’s fast enough to prototype with a relatively small model.

4

PNY DGX Spark Stacking Cable

Mfr Part# NJAAKKR-0006 (30 AWG)

Mfr Part# NJAAKK-0006 (32 AWG)

You can find them at MicroCenter at $99.00 . Mine purchased at Micro Center was made by Amphenol:

https://www.amphenol-cs.com/product/njaakr0006.html

https://www.amphenol-cs.com/product/njaakk0006.html

Other than the wire gauge they have the same specs - at 0.5m either should be fine.

5

There are two approved cable SKUs

6

Warning: this is not a good reference. You cannot use any random cable from this list. I bought the MCP1650-V00AE30 and it does not work.
7

I just ordered the NVIDIA/Mellanox MCP1650-V00AE30 Compatible 0.5m (1.6ft) 200G QSFP56 Passive Direct Attach Copper Twinax Cable 30AWG for DGX Spark Dual-System Interconnect from NADDOD. It is advertised as being compatible and they tell me they test each cable before shipping. I will let you know if it works.

I attended the Nvidia GTC in Washington last week and nobody–I mean nobody–had these cables for sale at the show, although a Dell guy tried to see if he could sell me one of their extras [but no]. An Nvidia guy I talked to said they had underestimated the demand and had only a single source.

There are a wide range of prices, too. The one I list above is $66 but shipping is $25 and I think it’s coming from China. Perhaps I will get a customs bill as well. But I ordered it yesterday and just got a notice from FedEx.

Here’s the link: Naddod cable