NVIDIA Mellanox MCX312A-XCAT ConnectX-3 EN Dual-Port SFP+ 10GbE PCIe Adapter: This is a standard PCIe add-in network interface card with two SFP+ ports at 10 Gb/s Ethernet. The EN suffix indicates Ethernet-only ConnectX-3 silicon — this card is not VPI and cannot run InfiniBand. This is a refurbished unit, tested in working order.
Engineering Context
The MCX312A-XCAT uses a PCIe 3.0 x8 8 GT/s host interface, which is comfortably wider than two 10 GbE ports require, leaving headroom for line-rate full-duplex traffic on both ports simultaneously. The ConnectX-3 EN ASIC supports stateless TCP/UDP offloads, hardware checksumming, LSO/LRO, RSS, RoCE v1/v2, and SR-IOV. Each SFP+ cage accepts standard 10GBASE-SR, 10GBASE-LR, or 10G DAC twinax cables. The card ships with both low-profile and full-height brackets in typical OEM packaging.
Deployment & Use Cases
10 GbE access-layer NICs in virtualization hosts running VMware ESXi, Hyper-V, or KVM. Storage front-ends for iSCSI, NFS-RDMA, and NVMe-oF over RoCE. Hadoop, Spark, and Ceph cluster nodes that need RDMA-capable 10GbE. Bonded LACP uplinks where each port carries a discrete VLAN trunk. Cost-effective replacement for failed Intel X520 or Broadcom 57810 dual-port 10GbE cards.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX312A-XCAT
ASIC: ConnectX-3 EN (Ethernet only)
Ports: 2 x SFP+
Speed: 10GbE per port (also 1GbE)
Host Bus: PCIe 3.0 x8 (8 GT/s)
Form Factor: Standard PCIe add-in (low-profile and full-height brackets)
Offloads: RoCE v1 / v2, SR-IOV, stateless TCP/UDP, RSS, LSO/LRO
Compliance: RoHS R6
Optic Compatibility: Standard 10GBASE-SR, 10GBASE-LR, 10G DAC
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Compatible with any 10GbE SFP+ switch — Mellanox SX1012/SX1024, Cisco Nexus 5000/9000 SFP+, Arista 7050S, Dell N4032 series — using SR/LR optics or 10G DAC. As an EN ConnectX-3 part, it does not enumerate as InfiniBand and cannot be flashed to VPI. Maximum line rate per port is 10 Gb/s; the card will not negotiate to 25GbE. PCIe 3.0 x8 host slot recommended; the card will operate in x4 slots but with reduced bus headroom.
Why Choose T.E.S IT-SOLUTIONS
Every MCX312A-XCAT shipped by T.E.S IT-SOLUTIONS is bench-tested for dual 10GbE link-up, PCIe link width, and RoCE function. We provide expert consultation on Ethernet fabric design, global shipping, and 1–3 day handling time.