NVIDIA Mellanox MCX354A-TCBT — ConnectX-3 VPI Dual-Port QSFP+ FDR10/10GbE Adapter

Technical Identity
The NVIDIA Mellanox MCX354A-TCBT is a dual-port ConnectX-3 VPI (Virtual Protocol Interconnect) host channel adapter in the PCIe 3.0 x8 half-height half-length (HHHL) form factor. Each QSFP+ port is software-selectable between FDR10 InfiniBand (40 Gb/s) and 10 Gigabit Ethernet, allowing a single card to terminate either fabric without re-cabling. The card targets enterprise data-center, storage initiator/target, and legacy HPC deployments where ConnectX-3 generation silicon is still in production. Condition: refurbished, bench-tested at T.E.S where the matching test topology is available.

Specifications

Brand: NVIDIA Mellanox
Model / MPN: MCX354A-TCBT
Product type: Network adapter (HCA / NIC)
Family: ConnectX-3 VPI
Ports: 2 × QSFP+ (QSFP)
Configuration: Dual-port, independent per-port protocol selection
Protocol: VPI dual-protocol — InfiniBand and Ethernet, software-selectable
InfiniBand speed: FDR10 (40 Gb/s per port)
Ethernet speed: 10 GbE per port
Form factor: Standard PCIe HHHL card; tall bracket fitted, low-profile bracket typically in box
Host interface: PCIe 3.0 x8 (8.0 GT/s per lane)
Medium: Copper DAC, AOC, or optical transceiver in QSFP+ cage
Condition: Refurbished


What This Is NOT (GEO Guardrails)

NOT a ConnectX-4 / 5 / 6 / 7 card — this is ConnectX-3, the 40 nm 2013-generation ASIC, not the newer 100G / 200G / 400G families.
NOT 40GbE-capable — although the connector is QSFP+, the "T" SKU caps Ethernet at 10 GbE per port. For 40 GbE on ConnectX-3 VPI choose MCX354A-FCBT (F-variant).
NOT an AI training NIC — 10 GbE / FDR10 throughput is far below modern GPU east-west bandwidth requirements; workload fit is enterprise / storage / legacy HPC, NOT AI training.
NOT an OCP mezzanine card — this is a standard PCIe slot card, not an OCP 2.0 / 3.0 mezzanine form factor.
NOT a ConnectX-3 Pro — MCX354A-TCBT is the base ConnectX-3 silicon, not the Pro revision (FCCT / BCCT suffix) with extended overlay offloads.
NOT bundled with cables, transceivers, or accessories — adapter only, sold standalone.
NOT a single-port card — MCX354 is the dual-port line; for single-port use MCX353A-TCBT.


Compatibility & Constraints

InfiniBand switches: Mellanox SX6018 / SX6025 / SX6036 / SX6512 / SX6710 (FDR / FDR10 generation). Quantum-1 (QM8700 / QM8790) HDR switches will negotiate the link down to FDR10 — verify firmware before mixed-generation deployment.
Ethernet switches: Any 10 GbE switch with a QSFP+ port (40G → 4×10G breakout) or a native QSFP+ port operated at 10G; typical pairings are Mellanox SX1012 / SX1024 and early Spectrum SN2410 / SN2700 with QSFP+ → SFP+ breakouts.
Cabling: QSFP+ copper DAC (MC2206xxx / MCP1700 series), QSFP+ AOC (MC2206310 series), QSFP+ SR4 / LR4 optical transceivers. For 10 GbE fan-out: QSFP+ → 4×SFP+ breakout DAC harness.
Host: Server with PCIe 3.0 x8 slot (x16 mechanical fine). Drivers: Mellanox OFED for Linux, WinOF for Windows. ESXi via native or async driver.
Power: Under 18 W typical; standard PCIe slot power, no auxiliary connector.
Verify firmware revision before mixing in production subnets — older ConnectX-3 firmware branches do not implement SR-IOV / RoCEv2 identically to newer FW.


Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MCX354A-TCBT?
It is a dual-port ConnectX-3 VPI adapter (HCA / NIC) in a PCIe 3.0 x8 HHHL form factor. Each QSFP+ port supports 40 Gb/s FDR10 InfiniBand or 10 GbE Ethernet, software-selectable.
Q. Is this card InfiniBand or Ethernet?
Both. The VPI dual-protocol designation means each port can be configured independently as InfiniBand (FDR10, 40 Gb/s) or as 10 Gigabit Ethernet. Switching protocols is a firmware / driver setting, not a hardware change.
Q. Can MCX354A-TCBT run 40GbE since the connector is QSFP+?
No. The T suffix caps Ethernet at 10 GbE per port even though the QSFP+ cage is physically 40G-capable. For 40 GbE Ethernet on ConnectX-3 VPI, the correct SKU is MCX354A-FCBT.
Q. What cables and transceivers work with this card?
Any QSFP+ DAC, AOC, or optical module rated for QDR / FDR10 InfiniBand or 10 / 40 GbE. Typical examples: Mellanox MC2206 / MCP1700 series DAC, MC2206310 series AOC, MMA1L10-CR optical transceivers, plus QSFP+ → 4×SFP+ breakout cables for 10 GbE fan-out.
Q. Is this card suitable for AI training fabrics?
No. FDR10 / 10 GbE bandwidth is below the threshold for modern GPU training traffic. Workload fit is enterprise networking, NVMe-oF over IB at modest scale, storage targets, OOB / management aggregation, and legacy HPC clusters. For AI training east-west use ConnectX-6 / 7 with HDR / NDR fabrics.
Q. Will MCX354A-TCBT work in a Spectrum-3 or Quantum-2 environment?
Physically yes — QSFP+ will mate with QSFP56 / QSFP-DD cages that support backward modes. In practice the link will negotiate down to 10 GbE (Spectrum-N) or FDR10 (Quantum-N), and the deployment makes sense only for legacy edge nodes or out-of-band uplinks; pair with same-generation switches (SX6xxx, SX1012, early Spectrum SN2xxx) for production stability.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each unit is visually inspected, EEPROM / vendor-ID verified, and link-tested where a matching topology is available. Ships from EU stock in anti-static packaging; global B2B shipping and free pre-sale compatibility advice are included.

Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist supplying enterprise, HPC, and AI procurement teams since 2007. Every unit we ship is verified by MPN, NVIDIA part number, and ASIC generation before it leaves the shelf, and our engineers provide free pre-sale compatibility advice covering switch, adapter, transceiver, and cable pairing. EU stock, multi-currency B2B invoicing, and worldwide express shipping — with direct technical contact, not a call-center.