Mellanox Q3400-RA 144-Port XDR InfiniBand Switch 4U Used
Quick answer: Mellanox Q3400-RA used, bench-tested. NVIDIA Quantum-3 Q3400-RA with 144 XDR ports over 72 OSFP cages at 400G, 4U, 8 power supplies, managed, C2P airflow — the high-density spine of the Quantum-3 400G InfiniBand family.
In stock: Q3400-RA 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 Q3400-RA) 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.
Mellanox Q3400-RA
The NVIDIA Quantum-3 Q3400-RA (920-9B36F-00RX-8S0) is the 4U high-density build of the Quantum-3 family: 144 XDR ports delivered over 72 OSFP cages, 400Gb/s per port and 57.6 Tb/s of aggregate InfiniBand bandwidth in a managed, standard-depth chassis with 8 power supplies for spine-level redundancy.
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 | Q3400-RA |
| Family | Mellanox |
| Switch silicon | NVIDIA Quantum-3 |
| Ports | 144 × 400G XDR (over 72 OSFP cages) |
| Port speed | 400Gb/s per port |
| Connectors | 72 × OSFP cages |
| Switching capacity | 57.6 Tb/s aggregate InfiniBand bandwidth |
| Latency | Sub-microsecond Mellanox SHARP-enabled fabric |
| Packet buffer | On-chip EDR/XDR shared buffer |
| Airflow | C2P — connector-to-power (back-to-front) |
| Form factor | 4U rackmount, standard depth |
| Dimensions | 4U chassis, standard depth, rail kit included |
| Power | 8 × hot-swap PSU (power cords not included) |
| Management | Managed platform (MLNX-OS), console + Ethernet management ports |
| Software | MLNX-OS / NVIDIA UFM ready |
Key features
- 144 × 400G XDR ports over 72 OSFP cages
- Quantum-3 InfiniBand silicon with SHARP, adaptive routing
- 8 hot-swap power supplies for spine-grade redundancy
- Managed (MLNX-OS) with console and management Ethernet
- 4U, standard depth, rail kit included
Typical deployments
AI/HPC training-fabric spines, large GPU cluster interconnect and storage fabrics that need 400G InfiniBand at high port density.
What is included
- Switch chassis with power supply sets
- Fan units
- Rail kit
- Condition report and bench-test notes
Not included
- OSFP optics and cables
- Software licence transfer paperwork
Q3400-RA in the lineup
Q3400-RA is the 4U high-density Quantum-3 build — double the OSFP cages of the 2U QM9700 series with 8 PSUs. If your rack needs 400G NDR ports instead, the QM9700/QM9790 are the matching platform.
How it compares with models we also stock
| Model | Fabric | Ports | Best for |
|---|---|---|---|
| Q3400-RA (this page) | InfiniBand XDR 400G | 144 over 72 OSFP | 4U high-density Quantum-3 spine |
| QM9790-NS2F | InfiniBand NDR 400G | 64 over 32 OSFP | 2U Quantum-2 leaf/spine |
| QM9700-NS2R | InfiniBand NDR 400G | 64 over 32 OSFP | 2U Quantum-2, C2P airflow |
| SB7700-ES2F | InfiniBand EDR 100G | 36 QSFP28 | 1U Switch-IB legacy clusters |
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 Q3400-RA, 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
How many ports does the Q3400-RA have?
144 XDR ports delivered over 72 OSFP cages — each cage carries two 400G XDR ports. The 4U chassis also holds 8 power supplies.
Is Q3400-RA Ethernet or InfiniBand?
InfiniBand only — it is a Quantum-3 XDR platform. There is no PoE on an InfiniBand switch; for 400G Ethernet look at the Spectrum-4 SN5600 family.
What speed is each port?
400Gb/s XDR per port, with 12-port lanes grouping into the 72 OSFP cages.
How does Q3400-RA compare with QM9700/QM9790?
Quantum-3 vs Quantum-2 generation: Q3400-RA gives 144 XDR ports in 4U with 8 PSUs, while QM9700/QM9790 give 64 NDR ports in 2U with 2 PSUs.
What warranty do you provide?
90-day warranty from delivery, after bench testing on our own line.
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.