NVIDIA Mellanox® MCX631435AN-GDAB ConnectX-6 Lx OCP 3.0 50GbE Single QSFP28 PCIe 4.0 x8 (Refurbished)
Technical Identity
The NVIDIA Mellanox® MCX631435AN-GDAB is a refurbished ConnectX-6 Lx Ethernet-only network adapter in OCP Spec 3.0 small form factor (SFF) mezzanine. ConnectX-6 Lx is the low-power, cost-optimized Ethernet-only variant of the ConnectX-6 family — it does NOT support InfiniBand. The card provides a single QSFP28 cage operating at 10/25/40/50 GbE on a PCIe 4.0 x8 host interface, with No Crypto and a Thumbscrew Pull-Tab bracket for tool-less install/removal in OCP 3.0 server sleds.
Specifications
Brand: NVIDIA Mellanox
Model / MPN: MCX631435AN-GDAB
Product family: ConnectX-6 Lx (Ethernet-only Lx ASIC)
Form factor: OCP Spec 3.0 SFF mezzanine
Network ports: 1× QSFP28
Port speeds: 10 / 25 / 40 / 50 GbE
Host interface: PCIe 4.0 x8 (backward compatible to PCIe 3.0)
Cryptography: No Crypto (-N suffix)
Management: Host management
Bracket: Thumbscrew Pull-Tab (tool-less)
Offloads: RoCE v2, SR-IOV, NVMe-oF, ASAP² (Open vSwitch HW offload)
Condition: Refurbished — Grade A, MPN- and EEPROM-verified, ESD-safe packaging
What This Is NOT
NOT a standard PCIe stand-up card — this is the OCP 3.0 mezzanine form factor (-435 suffix), requires an OCP 3.0 mezzanine slot in the server.
NOT InfiniBand-capable — ConnectX-6 Lx is Ethernet only (Lx ASIC). For VPI / IB use ConnectX-6 (MCX65xx/MCX66xx).
NOT a 100GbE card — Lx tops out at 50GbE per port. The QSFP28 cage will negotiate down from a 100GbE transceiver but will only link at up to 50GbE.
NOT a Multi-Host / Socket-Direct variant.
NOT bundled with transceivers, DAC/AOC cables, or thermal kits — sold standalone.
Compatibility and Hard Constraints
Server slot: requires an OCP Spec 3.0 SFF mezzanine slot — will not fit standard PCIe expansion slots. Verify your server platform (Dell PowerEdge, HPE ProLiant, Lenovo ThinkSystem, Supermicro, OCP-compliant chassis) exposes an OCP 3.0 bay.
Cabling: the QSFP28 port accepts QSFP28 50GbE DAC, AOC, or optical transceivers. 100GbE QSFP28 modules will physically fit and negotiate down to 50GbE. Use 25GbE breakout (QSFP28 → 4× SFP28) where the switch end supports it.
Switch pairing (Ethernet only): NVIDIA Spectrum / Spectrum-2 / Spectrum-3 Ethernet switches, or any 25/50/100GbE Ethernet switch with QSFP28 ports configured for 50GbE.
Software: MLNX_OFED / DOCA-Host for Linux, WinOF-2 for Windows Server — match the driver release to your kernel / OS version.
Frequently Asked Questions
Q. What is the MCX631435AN-GDAB?
ConnectX-6 Lx OCP 3.0: single 50GbE QSFP28, PCIe 4.0 x8, host management, No Crypto, Thumbscrew bracket.
Q. What is the Thumbscrew Pull Tab bracket?
Tool-less bracket for easy install/removal without screwdrivers — standard in high-density OCP server deployments.
Q. Does 50GbE work with standard QSFP28 infrastructure?
Yes — QSFP28 supports 40G/50G/100G modes. Switch port must be configured for 50GbE operation.
Q. What offloads does MCX631435AN-GDAB support?
RoCE v2, NVMe-oF, and SR-IOV hardware virtualization.
Q. What condition does T.E.S IT-SOLUTIONS supply?
Refurbished Grade A — EEPROM-verified, cosmetically inspected, EU stock.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based NVIDIA Mellanox specialist serving HPC, AI, and enterprise data-center procurement teams since 2007. We carry ConnectX-6 Lx in both OCP 3.0 and standard PCIe form factors at 10/25/50GbE port speeds, with full MPN and ASIC-generation verification on every unit. Multi-currency B2B invoicing, EU stock with worldwide express options, ESD-safe packaging, and direct engineering consultation on switch / adapter / cable pairing — not a call-center.