Mellanox QM9790-NS2F 400Gb/s NDR InfiniBand Switch 64-Port Used
Quick answer: NVIDIA Quantum-2 QM9790 MQM9790-NS2F used, bench-tested. NVIDIA Quantum-2 QM9790 with 64 NDR 400Gb/s ports on 32 OSFP cages, 51.2 Tb/s bidirectional, 1U, P2C airflow, and no on-board subnet manager — the fabric is driven by UFM or OpenSM from a host.
In stock: MQM9790-NS2F is in stock — availability is confirmed per part number, so send the exact model you need and we check the shelf before quoting.
Need a quote? Message WhatsApp +86 13068616914 with the part number (for example MQM9790-NS2F) and the quantity — we reply with price, condition notes and photos of the actual unit. No price is listed here because every order is quoted per part number.
NVIDIA Quantum-2 QM9790
The NVIDIA Quantum-2 QM9790 is the externally managed member of the QM9700 series: 64 non-blocking NDR 400Gb/s InfiniBand ports on 32 OSFP cages in a 1U chassis, 51.2 Tb/s of bidirectional bandwidth, and in-network computing through SHARPv3. Because the subnet manager lives outside the switch, one UFM or OpenSM instance can drive a whole fabric instead of one manager per box.
Condition: Used — cleaned, re-flashed and bench-tested on our own test line before it is listed. 90-day warranty from delivery.
| Specification | Details |
|---|---|
| Part number | MQM9790-NS2F |
| Family | NVIDIA Quantum-2 QM9790 |
| Switch silicon | NVIDIA Quantum-2 (switch IC for NDR 400Gb/s InfiniBand) |
| Ports | 64 × 400Gb/s NDR, 32 OSFP cages; up to 128 × 200Gb/s with splitters |
| Port speed | 400Gb/s NDR per port (200Gb/s per port with 2-way split) |
| Connectors | OSFP (32 cages, 64 ports) |
| Switching capacity | 51.2 Tb/s bidirectional, non-blocking |
| Packet buffer | Shared buffer with adaptive routing and congestion control |
| Airflow | P2C — power-to-connector (front-to-back) |
| Form factor | 1U rackmount |
| Dimensions | 43.6 × 438 × 660 mm |
| Power | 2 × hot-swap PSU (1+1), 200-240 VAC |
| Management | Externally managed — subnet manager runs on a host (OpenSM) or NVIDIA UFM |
| Software | NVIDIA UFM / MLNX-OS fabric software |
Key features
- 64 × NDR 400Gb/s non-blocking ports on 32 OSFP cages
- Up to 128 × 200Gb/s ports using 2-way port splitting
- SHARPv3 in-network aggregation for collective operations
- Adaptive routing and congestion control for lossless fabrics
- Backward compatible with HDR 200G, EDR 100G and FDR links
- Fat tree, DragonFly+, SlimFly and multi-dimensional torus topologies
Typical deployments
GPU training clusters, HPC fabrics, storage backbones for Lustre and GPFS, and super-spine layers where central UFM telemetry is preferred over per-switch management.
What is included
- Switch chassis with both power supplies
- Fan units as configured for P2C airflow
- Rack mounting kit
- Condition report and bench-test notes for the unit you receive
Not included
- OSFP transceivers and cables
- Subnet manager licence (UFM) or OpenSM host
- Rails for non-standard racks
MQM9790-NS2F in the lineup
Within the QM9700 series the difference is management, not bandwidth: QM9700 carries an on-board subnet manager for fabrics up to about 2,000 nodes, while QM9790 leaves the manager external so a single UFM instance can cover a larger fabric with one consistent telemetry view. Ports, speed and airflow options are the same.
How it compares with models we also stock
| Model | Fabric | Ports | Best for |
|---|---|---|---|
| MQM9790-NS2F | InfiniBand NDR 400G | 64 (32 OSFP) | Large fabrics run from UFM/OpenSM |
| MQM9700-NS2F | InfiniBand NDR 400G | 64 (32 OSFP) | Standalone fabrics up to ~2,000 nodes |
| MSB7700-ES2F | InfiniBand EDR 100G | 36 QSFP28 | EDR estates and mixed-generation fabrics |
Why buy this switch from Zhongxin Data
- Bench-tested on our own in-house test line — ports, fans and power supplies are checked before the unit leaves.
- We quote only what we can physically confirm: the exact part number, airflow direction and condition notes come from the unit in front of us.
- Used enterprise switches at secondary-market pricing, with a 90-day warranty from delivery.
- Worldwide shipping from Hong Kong, China; consolidation with servers, NICs and optics from the same rack is routine.
Request a quote
Send the part number MQM9790-NS2F, the quantity you need and your destination to WhatsApp +86 13068616914 (or reply to any thread on zhongxindata.hk). We confirm availability against the exact model before quoting, and we can quote alternative airflow builds or port-count variants from the same family if they fit your rack better.
Frequently asked questions
What is the difference between QM9790 and QM9700?
Management. QM9790 has no on-board subnet manager, so UFM or OpenSM runs on a host. QM9700 includes an on-board subnet manager for fabrics up to roughly 2,000 nodes. Ports, speed and airflow are the same.
Is this switch managed or unmanaged?
It is externally managed. The chassis boots as a fabric device and relies on an external subnet manager; plan for UFM or an OpenSM host before you deploy it.
What does NS2F mean?
N for NDR, S2 for the standard-depth 1U chassis, F for power-to-connector (front-to-back) airflow. The reverse-airflow version is NS2R.
Can I run 200Gb/s ports on it?
Yes. Each 400Gb/s port splits two ways, giving up to 128 ports of 200Gb/s with the right cables.
Does it work with HDR or EDR adapters?
Yes. The Quantum-2 platform negotiates down to HDR 200G, EDR 100G and FDR, so mixed-generation fabrics work at the speed of the slower link.
Is it Ethernet or InfiniBand?
InfiniBand. This is a Quantum-2 fabric switch for native IB verbs. For RoCEv2 over Ethernet, look at the Spectrum SN series instead.
How is it shipped and covered?
Cleaned, re-flashed and bench-tested on our own test line, with a 90-day warranty from delivery. Ask for photos of the actual unit before you commit.
Available at Zhongxin Data — enterprise network hardware specialists. Worldwide shipping from Hong Kong, China.
Product image is a reference image for the form factor — revision, label and airflow sticker vary by batch. Ask us for photos of the actual unit before you commit.