NVIDIA Mellanox MCX312A-XCBT ConnectX-3 EN 10GbE Dual-Port SFP+ PCIe3.0 x8 NIC: This is a dual-port 10 Gigabit Ethernet network interface card (NIC) based on the ConnectX-3 EN ASIC. MPN MCX312A-XCBT. This is a server adapter card, not a switch, optical transceiver, or storage controller. This is a refurbished unit, fully tested.
Engineering Context
The MCX312A-XCBT uses Mellanox ConnectX-3 EN silicon with two SFP+ cages, providing 10GbE per port. The host interface is PCI Express 3.0 x8 at 8 GT/s, sufficient to drive both 10GbE ports at line rate. The adapter implements stateless offloads (TCP/UDP/IP checksum, TSO/LSO, RSS) and supports RDMA over Converged Ethernet (RoCE). Single-Root I/O Virtualization (SR-IOV) is supported for virtualized workloads. Power draw is well under 25W typical for 10GbE dual-port ConnectX-3 EN.
Deployment & Use Cases
Server-side 10GbE connectivity in virtualized environments (VMware ESXi, KVM, Hyper-V) leveraging SR-IOV. Storage server uplinks for iSCSI, NFS, and SMB Direct. RoCE-enabled fabrics for low-latency database replication and HPC scratch storage. OpenStack compute and network nodes requiring 2x10GbE NIC bonding for high availability.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX312A-XCBT
Product Family: ConnectX-3 EN
Form Factor: PCIe Half-Height, Half-Length (HHHL)
Host Bus: PCI Express 3.0 x8 (8 GT/s)
Ports: 2 (Dual-Port)
Connector: SFP+
Data Rate: 10GbE per port
Protocol: Ethernet
Offloads: TCP/UDP/IP checksum, LSO, RSS, RoCE, SR-IOV
Driver Support: MLNX_OFED (Linux), WinOF (Windows)
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Requires a PCIe 3.0 x8 or larger slot for full bandwidth; physically fits x16 slots and will operate at reduced throughput in x4 slots. Compatible with SFP+ DAC copper cables and SR/LR optical transceivers using SFP+ form factor. This is an Ethernet-only adapter (ConnectX-3 EN), not a VPI part — it does not support InfiniBand modes. Not compatible with QSFP, SFP28, or RJ45 ports. Bracket type (standard or low-profile) varies by stock; refer to listing photos.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS tests every ConnectX-3 NIC for PCIe link training, 10GbE port functionality on both ports, and firmware integrity before shipment. We provide expert consultation on Mellanox Ethernet fabric design, 1–3 day handling time, EU shipping, and post-sale technical support.