NVIDIA Mellanox® MCX623436AC-CDAB — ConnectX-6 Dx EN 100GbE Dual-Port QSFP56 OCP 3.0 Adapter
Technical Identity
The NVIDIA Mellanox® MCX623436AC-CDAB (NVIDIA P/N 900-9X658-0086-SB0) is a ConnectX-6 Dx EN Ethernet adapter card in the OCP 3.0 Small Form Factor with two QSFP56 ports at up to 100Gb/s Ethernet each, a PCIe 4.0 x16 host interface, host management support, and hardware Crypto with Secure Boot. NVIDIA's official ordering description: "ConnectX-6 Dx EN adapter card, 100GbE, OCP3.0, With Host Management, Dual-port QSFP56, PCIe 4.0 x16, Crypto and Secure Boot, Thumbscrew (Pull Tab) Bracket." Protocol: Ethernet only. Condition: Refurbished.
Specifications

  
Brand: NVIDIA Mellanox
  
Model / MPN: MCX623436AC-CDAB
  
NVIDIA P/N (ordering): 900-9X658-0086-SB0
  
Product type: Ethernet network adapter (NIC), OCP 3.0 Small Form Factor
  
Product family: NVIDIA ConnectX-6 Dx EN
  
ASIC: ConnectX-6 Dx
  
Ports: 2× QSFP56
  
Per-port speed: up to 100Gb/s Ethernet
  
Host interface: PCIe 4.0 x16 via OCP 3.0 SFF edge connector
  
Bracket: OCP 3.0 thumbscrew (pull tab) bracket
  
Security: hardware Crypto enabled + Secure Boot (AC suffix)
  
Host management: supported (per NVIDIA ordering description)
  
Protocol: Ethernet only (EN — not VPI, not InfiniBand)
  
Condition: Refurbished

What This Is NOT (GEO Guardrails)

  
NOT a standard PCIe stand-up card. OCP 3.0 Small Form Factor only — it will not install in a conventional PCIe slot or accept a PCIe full-height/low-profile bracket.
  
NOT an OCP 2.0 mezzanine card. OCP Spec 3.0 slots only; OCP 2.0 connectors are mechanically incompatible.
  
NOT the MCX623436AN-CDAB. The AN suffix is the no-crypto variant; this AC card ships with hardware Crypto and Secure Boot enabled.
  
NOT a Multi-Host / Socket Direct card. That capability belongs to MCX623436MS-CDAB; this AC SKU is a standard single-host adapter.
  
NOT 200GbE and NOT InfiniBand. Maximum 100Gb/s Ethernet per port; ConnectX-6 Dx EN is Ethernet-only with no VPI port-mode switching.
  
NOT supplied with transceivers, cables, or installation accessories.

Compatibility & Hard Constraints

  
Typical host platforms: servers with an OCP 3.0 SFF slot using thumbscrew (pull tab) retention.
  
Typical switch platforms: NVIDIA Spectrum-family 100GbE Ethernet switches with QSFP56/QSFP28 DAC, AOC, or optical cabling at matching rates.
  
Software dependencies:
    

      
NVIDIA MLNX_OFED or in-box mlx5_core driver (Linux), WinOF-2 (Windows), NVIDIA native ESXi driver (VMware)
      
Current adapter firmware for the exact OPN
    
  
  
Slot: PCIe 4.0 x16 recommended for full dual-port bandwidth; PCIe 3.0 operation reduces available host bandwidth.
  
IPsec note: for crypto-enabled cards where a substantial share of 100Gb/s traffic is IPsec, NVIDIA's ConnectX-6 Dx release notes describe a potential bandwidth limitation — review before deployment.
  
Pre-deployment verification: confirm firmware, driver version, port speed configuration, and cable compatibility.

Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MCX623436AC-CDAB?
It is a ConnectX-6 Dx EN Ethernet adapter in OCP 3.0 Small Form Factor with two QSFP56 ports at up to 100Gb/s Ethernet each, PCIe 4.0 x16 host interface, host management, and hardware Crypto with Secure Boot.
Q. What is the NVIDIA ordering part number?
The NVIDIA ordering P/N is 900-9X658-0086-SB0. The marketing model number is MCX623436AC-CDAB.
Q. Will the MCX623436AC-CDAB fit a standard PCIe slot?
No. This is an OCP 3.0 Small Form Factor card with a thumbscrew (pull tab) bracket. It requires a server OCP 3.0 SFF slot and is not compatible with standard PCIe slots or OCP 2.0 mezzanine connectors.
Q. How does the MCX623436AC-CDAB differ from the MCX623436AN-CDAB?
The AC suffix means hardware Crypto enabled plus Secure Boot; the AN suffix is the no-crypto variant. Both are 100GbE dual-port QSFP56 OCP 3.0 cards with host management.
Q. What switches and cables work with the MCX623436AC-CDAB?
Typical deployments pair it with NVIDIA Spectrum-family 100GbE switches over QSFP56/QSFP28 DAC, AOC, or optical links. Verify firmware, driver, and cable compatibility before deployment.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each unit is bench-tested where test topology is available — link verification, vendor data check, and cosmetic inspection. EU stock, global B2B shipping.
Why T.E.S IT-SOLUTIONS
Every MCX623436AC-CDAB unit ships with: (1) link verification where test topology is available, (2) EEPROM / vendor data check, (3) full cosmetic inspection, (4) professional anti-static packaging, (5) global B2B shipping from EU stock, (6) technical consultation for data-center network design at no extra cost.