Identity & Definition
The NVIDIA Mellanox MCX314A-BCAT is a 40GbE enterprise Ethernet network interface card (NIC) in refurbished condition. This dual-port QSFP adapter is based on Mellanox ConnectX-3 EN technology and connects via PCIe 3.0 x8 for high-bandwidth server networking. The MCX314A-BCAT is an Ethernet-only adapter — it is NOT a VPI (InfiniBand + Ethernet) card, NOT a single-port device, and NOT an OCP form factor card. It ships with a full-height (tall) bracket.
Engineering Context
The MCX314A-BCAT delivers 40Gb/s per port (80Gb/s aggregate) over its two QSFP ports. The adapter connects to the host via a PCIe 3.0 x8 interface. ConnectX-3 EN technology supports hardware offloads including SR-IOV for NIC virtualization (up to 128 VFs per port), stateless TCP/UDP/IP offload, and RoCE (RDMA over Converged Ethernet) v1 for low-latency storage and cluster communication. The card also supports VXLAN and NVGRE hardware offload for overlay network acceleration.
Deployment & Use Cases
The MCX314A-BCAT is deployed for 40GbE server uplinks in data center aggregation and access layers. Typical use cases include VMware ESXi and Hyper-V virtualization hosts requiring SR-IOV passthrough, iSCSI and NFS storage network connections, spine-to-leaf 40GbE fabric links in enterprise and cloud compute environments, and high-throughput workloads such as media streaming, backup, and replication. The dual-port design supports network redundancy, link aggregation (LACP), or dual-network segmentation.
Technical Specifications

Part Number (MPN): MCX314A-BCAT
Adapter Family: ConnectX-3 EN
Adapter Type: Ethernet Network Interface Card (NIC)
Port Count: 2 (Dual-Port)
Port Type: QSFP
Data Rate: 40Gb/s per port (80Gb/s aggregate)
Host Interface: PCIe 3.0 x8
Form Factor: Full-Height (Tall Bracket) PCIe Add-in Card
Protocols: 40GbE, RoCE v1, SR-IOV, VXLAN/NVGRE offload
Condition: Refurbished

Compatibility & Hard Constraints
The MCX314A-BCAT requires a PCIe 3.0 x8 or wider slot. The QSFP ports accept 40GbE QSFP+ transceivers, 40GbE QSFP+ DAC cables, or QSFP+-to-4xSFP+ breakout cables for 4x10GbE operation. It is NOT compatible with QSFP28 100GbE optics at 100GbE speeds — the ConnectX-3 EN chipset supports a maximum of 40Gb/s per port. For 100GbE requirements, consider the ConnectX-4 or ConnectX-5 product families. The successor model in the ConnectX-4 generation is the MCX416A-BCAT.
Why Choose T.E.S IT-SOLUTIONS
Every MCX314A-BCAT adapter sold by T.E.S IT-SOLUTIONS is functionally tested and verified before shipment. Our team provides technical consultation on NVIDIA Mellanox NIC compatibility, transceiver selection, and deployment planning. Orders ship within 1–3 business days with worldwide delivery and protective packaging.