NVIDIA Mellanox MCX4121A-ACUT ConnectX-4 Lx EN Adapter, 25GbE, Dual-Port SFP28, PCIe 3.0 x8, UEFI Enabled: This enterprise network interface card (NIC) is the NVIDIA Mellanox ConnectX-4 Lx, part number MCX4121A-ACUT. It is a dual-port 25 Gigabit Ethernet adapter based on the ConnectX-4 Lx ASIC. The ACUT suffix indicates Ethernet-only with crypto enabled, UEFI PXE boot support, and a tall bracket. This is a refurbished unit, tested by T.E.S IT-SOLUTIONS.
Engineering Context
The ConnectX-4 Lx is the cost-optimized member of the ConnectX-4 family, delivering 25 Gb/s per port (50 Gb/s aggregate) through two SFP28 ports over a PCIe 3.0 x8 host interface (63 Gb/s bidirectional bandwidth). The Lx variant supports hardware offloads including RoCE v2, VXLAN/NVGRE encapsulation, and SR-IOV (up to 512 VFs). The UEFI-enabled firmware supports PXE boot over 25GbE, enabling network-based OS deployment in modern UEFI environments. Each SFP28 port is backward-compatible with SFP+ at 10GbE. Power consumption is typically under 16W for both ports.
Deployment & Use Cases
Dual-port 25GbE server connectivity for cloud and enterprise data centers migrating from 10GbE. NVMe-oF and iSCSI storage networking at 25 Gb/s per port with RDMA (RoCE v2). Virtualized environments on VMware ESXi, Hyper-V, or KVM with SR-IOV for VM-level network isolation. UEFI PXE boot deployments for automated OS provisioning over 25GbE. HPC cluster interconnect where dual-port 25GbE provides redundancy or separate data/management networks.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX4121A-ACUT
ASIC: ConnectX-4 Lx
Type: Ethernet Network Adapter (NIC)
Speed: 25GbE per port (also supports 10GbE with SFP+)
Ports: 2x SFP28
Host Interface: PCIe 3.0 x8
Protocols: RoCE v2, VXLAN, NVGRE, SR-IOV
SR-IOV VFs: Up to 512
UEFI PXE Boot: Enabled
Power Consumption: ~16W typical
Bracket: Tall (Full-Height)
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Ethernet Only: ConnectX-4 Lx does not support InfiniBand. For InfiniBand, use ConnectX-4 VPI variants (MCX455A or MCX456A series). SFP28 Ports: Accepts SFP28 (25GbE) and SFP+ (10GbE) transceivers and cables. Does not accept QSFP modules. PCIe 3.0 x8: Requires a physical x8 or x16 slot. Will operate at reduced bandwidth in x4 slots. Dual Port: Two SFP28 ports. For single-port 25GbE, use MCX4111A-ACAT. UEFI Required: PXE boot feature requires UEFI-capable server firmware. Legacy BIOS PXE may require different firmware configuration. Predecessor: ConnectX-3 Pro EN (10GbE dual-port). Successor: ConnectX-5 EN (25/50GbE).
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS tests every refurbished ConnectX-4 Lx adapter for dual-port connectivity, PCIe link negotiation, and firmware integrity. We provide expert consultation on NIC selection, firmware compatibility, and network architecture planning. Global shipping with 1–3 business day handling and full tracking.