NVIDIA Mellanox MCX4121A-XCAT ConnectX-4 Lx EN, Dual-Port 10GbE SFP28, PCIe 3.0 x8 (Tall Bracket): This is a dedicated 10GbE Ethernet network interface card based on the ConnectX-4 Lx ASIC, not a Virtual Protocol Interconnect (VPI) adapter and not a 25GbE-capable variant. The -XCAT SKU is the 10GbE-only configuration of the MCX4121A series; the 25GbE-capable counterpart is MCX4121A-ACAT. Ships with a tall (full-height) PCIe bracket. This is a refurbished unit.
Engineering Context
ConnectX-4 Lx is NVIDIA's cost-optimized Ethernet line for 1/10/25/40/50GbE, with the -XCAT bin locked to 10GbE per port. The card supports RDMA over Converged Ethernet (RoCEv1/v2), SR-IOV with up to 128 virtual functions, hardware checksum and TSO/LSO offloads, and overlay-network offload for VXLAN, NVGRE, and GENEVE. PCIe 3.0 x8 provides ~64Gb/s of bidirectional host bandwidth — sufficient for two saturated 10GbE ports. The dual SFP28 cages physically accept SFP28 and SFP+ media; only 10GbE link rates are supported on this SKU.
Deployment & Use Cases
Cost-effective 10GbE server access for general enterprise virtualization (VMware ESXi, KVM, Hyper-V). NFS/iSCSI storage front-end at 10GbE. Open vSwitch hardware-offload at 10G. RoCE-capable NVMe-oF initiator side at 10G. Edge compute and ROBO 10GbE NIC refresh at low capex.
Technical Specifications
- OEM: NVIDIA Mellanox
- Part Number: MCX4121A-XCAT
- Series: ConnectX-4 Lx EN
- Network Ports: 2 × SFP28 (10GbE only on this SKU)
- Maximum Per-Port Rate: 10GbE
- Host Interface: PCI Express 3.0 x8
- RDMA: RoCE v1 / v2 supported
- SR-IOV: Up to 128 virtual functions
- Overlay Offload: VXLAN, NVGRE, GENEVE
- Bracket: Tall (full-height)
- Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
This is a 10GbE-only SKU — it will NOT link at 25GbE even with 25G optics installed; for 25GbE use MCX4121A-ACAT. Requires a free PCIe 3.0 x8 (or wider) slot; will down-train but continue to operate in PCIe 2.0 slots with reduced bandwidth. Ships only with a tall bracket; a low-profile bracket is not included. Compatible with NVIDIA-branded SFP+ and SFP28 transceivers and DAC/AOC; third-party optics may require coding for the host platform. RDMA features require RoCE-capable switching and DCB/PFC configuration on the fabric.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS validates every ConnectX-4 Lx adapter on a live PCIe 3.0 host with link-up tests on both ports and current firmware verification. Visit www.tes-itsolutions.com. Standard handling time 1–3 business days.