MSI EdgeXpert MS-C931 Cluster Cable: 0.5m QSFP112 400G DAC
To cluster two MSI EdgeXpert MS-C931 desktops you need one 0.5m QSFP112 400G passive DAC cable in the QSFP112 port on each unit. The EdgeXpert is MSI's GB10 Grace Blackwell box and carries the same NVIDIA ConnectX-7 NIC as the DGX Spark, so it uses the exact cable NVIDIA approves in its Spark Stacking documentation (Amphenol NJAAKK0006 / Luxshare LMTQF022-SD-R spec). Petronella Technology Group, Inc. sells it at $159 with free US shipping, in stock, shipping in 1 to 3 business days. As of August 2026, retail listings for the same NVIDIA-approved spec run $176 to $285, NVIDIA's own marketplace lists it at $99.99 but is chronically out of stock, and Amphenol's factory-direct store shows its whole QSFP112 line on backorder.
The MSI EdgeXpert MS-C931 leans on a vapor-chamber cooling design that MSI positions for steadier clocks under sustained load, which makes it a common pick for builders who plan to keep a clustered pair pinned at high utilization. None of that changes the interconnect: two EdgeXpert units still talk over the same single QSFP112 DAC, and that cable is the part that is hardest to source.
| Cable | 0.5m QSFP112 400G passive direct-attach copper (DAC) |
| Approved spec | Amphenol NJAAKK0006 / Luxshare LMTQF022-SD-R (NVIDIA Spark Stacking docs) |
| Fits | Both QSFP112 ports on the MSI EdgeXpert MS-C931 ConnectX-7 NIC |
| For two units | One cable |
| For a three-node ring | Three cables (switchless, each box uses both ports) |
| Price | $159, free US shipping (in stock, ships in 1 to 3 business days) |
Clustering your MSI EdgeXpert MS-C931 units: how many cables and when you need a switch
Each MSI EdgeXpert MS-C931 has two QSFP112 ports, so it follows the NVIDIA-documented GB10 topology: two units link directly with one cable, and three units form a switchless ring with three cables (NVIDIA's "Connect Three DGX Spark in a Ring Topology" playbook, each box using both ports for full pairwise connectivity). Three nodes is the switchless ceiling - with only two ports per unit, four or more units need a 200G-class QSFP switch. Clustering pools memory to run a model too large for one 128 GB node; it is a capacity play, not a speed boost, since each link runs around 25 GB/s.