NVIDIA Mellanox MCX631432AE-ADAB ConnectX-6 Lx EN, Dual-Port 25GbE SFP28, OCP 3.0, PCIe 4.0 x8, Crypto-Enabled: This is a ConnectX-6 Lx EN OCP 3.0 network adapter with two SFP28 ports each capable of 25GbE Ethernet. NVIDIA P/N is 900-9X625-0063-SB0. The card uses an OCP 3.0 thumbscrew/pull-tab bracket and supports hardware crypto offload but does not support Secure Boot. This is not a standard PCIe edge adapter; it requires an OCP 3.0 mezzanine slot, not a regular PCIe slot. This is a refurbished unit.
Engineering Context
The ConnectX-6 Lx ASIC implements PCIe 4.0 x8 to the host, doubling per-lane bandwidth versus PCIe Gen3. The crypto engine on this SKU performs in-line IPsec and TLS offload at line rate for 25GbE flows. SFP28 supports both passive copper DAC and SR/LR optical modules at 25GbE. The OCP 3.0 form factor allows external (front-panel) port access on hyperscale chassis without consuming an internal PCIe slot. Crypto-enabled (suffix 'AE'), no Secure Boot.
Deployment & Use Cases
Hyperscale and cloud OCP-compliant servers requiring dual 25GbE uplinks. Virtualization hosts running VMware ESXi or KVM with SR-IOV passthrough. Storage targets using RoCEv2 or NVMe-oF over 25GbE. Compliance-driven environments needing in-line IPsec/TLS encryption. East-west traffic between leaf-spine racks at 25GbE rate.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX631432AE-ADAB (NVIDIA P/N: 900-9X625-0063-SB0)
Family: ConnectX-6 Lx EN
Port Configuration: Dual SFP28
Data Rate: 25GbE per port
Host Interface: PCIe 4.0 x8
Form Factor: OCP 3.0 (Thumbscrew / Pull-Tab)
Crypto: Enabled (in-line IPsec/TLS offload)
Secure Boot: Not supported on this SKU
Offloads: RoCEv2, NVMe-oF, SR-IOV (firmware-dependent)
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Constraints
Requires an OCP 3.0 SFF (Small Form Factor) slot, not a standard PCIe edge slot. PCIe 4.0 x8 host preferred; PCIe Gen3 x8 negotiates down with reduced peak throughput. Compatible with NVIDIA Spectrum SN2000/SN3000 25GbE switches and other 25GbE leaf switches via SFP28 DAC or optics. SFP28 DACs and optics must be NVIDIA-coded or vendor-acceptable per host firmware policy. Not compatible with QSFP/QSFP28 cages without active SFP28-to-QSFP adaptation. This SKU does NOT support Secure Boot; do not deploy in environments requiring authenticated firmware boot.
Why TES
T.E.S IT-SOLUTIONS tests both SFP28 ports for link training on copper and optical media, verifies PCIe Gen4 x8 negotiation, and inspects the OCP 3.0 connector before shipment. See T.E.S IT-SOLUTIONS for OCP 3.0 host compatibility checks. Handling time is 1–3 business days.