NVIDIA Mellanox MCX516A-BDAT ConnectX-5 Ex EN 40GbE Dual-Port QSFP28 PCIe Gen4 x16 Network Adapter: This is a dual-port 40Gb/s Ethernet network interface card based on the ConnectX-5 Ex ASIC, with a PCIe Gen 4.0 x16 host interface and a tall bracket. This is a network adapter card, not a switch, transceiver, or breakout cable. This is a refurbished unit, tested by T.E.S IT-SOLUTIONS.
Engineering Context
The MCX516A-BDAT provides up to 80 Gb/s of aggregate Ethernet throughput across two QSFP28 ports configured for 40GbE. The QSFP28 form factor allows future flexibility for higher-speed transceivers if firmware permits. PCIe Gen 4.0 x16 provides ~256 Gb/s of host bandwidth, more than sufficient to saturate both 40GbE ports without contention. The ConnectX-5 Ex ASIC delivers RoCE v2, NVMe-oF, GPUDirect RDMA, and overlay tunnel offloads (VXLAN, Geneve, NVGRE), with single-digit microsecond RDMA latency.
Deployment & Use Cases
40GbE upgrades for legacy server fleets where 100GbE switching is not yet deployed. Dense virtualization hosts running SR-IOV with VXLAN overlay for tenant isolation. NVMe-over-Fabrics storage at moderate bandwidth tiers. Branch and edge data centers with mixed-speed fabrics. Lab and test environments retaining 40GbE switch infrastructure.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX516A-BDAT
Product Family: ConnectX-5 Ex EN
Ports: 2 × QSFP28
Max Data Rate: 40GbE per port (80 Gb/s aggregate)
Host Interface: PCIe Gen 4.0 x16 (backward compatible with Gen 3.0)
Protocol: Ethernet (10/25/40GbE)
Form Factor: Standard PCIe HHHL with tall bracket
Offloads: RoCE v2, Overlay (VXLAN/Geneve/NVGRE), TCP/UDP/IP stateless, T10-DIF, NVMe-oF
Virtualization: SR-IOV, VirtIO acceleration
Management: NC-SI
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Compatible with x86 servers providing PCIe Gen 4.0 x16 (or Gen 3.0 x16 at reduced bandwidth) and Linux/Windows drivers from NVIDIA. Pairs with NVIDIA Spectrum and any 40GbE-capable QSFP+ or QSFP28 switch using compatible 40GbE optics, AOCs, or DACs. This is an Ethernet-only (EN) adapter; it does not run InfiniBand. Maximum line rate is 40GbE per the SKU SPN; do not assume 100GbE without confirming firmware. Not compatible with OCP 3.0 chassis (this is a standard PCIe HHHL card). Tall bracket installed; low-profile bracket not included.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS bench-tests every refurbished ConnectX adapter for link, PCIe negotiation, and offload functionality before shipment. We provide expert consultation on Ethernet fabric design, global shipping, and a typical handling time of 1–3 business days.