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Nvidia Mellanox ConnectX-4 Lx CX4121A Dual Port SFP28 25GbE PCIe 3.0 x8 Network Interface Card (NIC) MCX4121A-ACAT

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SKU MCX4121A-ACAT
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  • Specifications
  • Description
Manufacturer Part Number MCX4121A-ACAT
Manufacturer Nvidia / Mellanox
Condition Refurbished
Standard Warranty 90 Day Replacement Warranty
Item Category Network Interface Cards (NICs)
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Nvidia Mellanox ConnectX-4 Lx CX4121A Dual Port SFP28 25GbE PCIe 3.0 x8 Network Interface Card (NIC) MCX4121A-ACAT

The NVIDIA Mellanox ConnectX-4 Lx (Models: CX4121A / CX4121C, Part Number: MCX4121A-ACAT) is a high-performance dual-port 25GbE Ethernet adapter designed for enterprise servers, virtualization, cloud infrastructure, software-defined storage, and high-speed networking environments. It utilizes a PCIe 3.0 x8 host interface and delivers advanced networking offload capabilities with low latency and high throughput.

Core Specifications

  • Manufacturer: NVIDIA / Mellanox
  • Series: ConnectX-4 Lx
  • Model: CX4121A / CX4121C
  • Part Number: MCX4121A-ACAT
  • Host Interface: PCI Express 3.0 x8
  • Port Configuration: Dual Port
  • Port Type: 2 x SFP28
  • Supported Ethernet Speeds: 1GbE, 10GbE, 25GbE
  • Form Factor: Low Profile / Half Height
  • Network Technology: Ethernet
  • Device Type: Network Interface Card (NIC)

Performance Features

  • High-performance dual-port Ethernet adapter
  • Supports 25GbE connectivity
  • Low-latency networking architecture
  • Advanced packet processing capabilities
  • Hardware acceleration for network workloads
  • Optimized for cloud and enterprise environments
  • High throughput for data-intensive applications

Enterprise Features

  • RoCE (RDMA over Converged Ethernet) Support
  • RoCE v1 and RoCE v2 Compatible
  • SR-IOV Virtualization Support
  • VXLAN Offload Support
  • NVGRE Offload Support
  • GENEVE Offload Support
  • Hardware-Based Traffic Acceleration
  • CPU Offloading Technologies
  • Software-Defined Storage Acceleration
  • Virtual Machine Networking Optimization

Operating System Compatibility

Compatible with major enterprise operating systems including:

  • Microsoft Windows Server
  • Linux
  • VMware ESXi
  • Citrix Hypervisor
  • FreeBSD

Physical Specifications

  • Low Profile Adapter Design
  • PCIe 3.0 x8 Interface
  • Dual SFP28 Network Ports
  • Enterprise Data Center Form Factor

CX4121A vs CX4121C

CX4121A and CX4121C are functionally the same hardware platform.

CX4121A

  • Standard Mellanox retail designation
  • Commonly referenced in Mellanox documentation
  • Associated with MCX4121A adapter family
  • Standard NVIDIA/Mellanox firmware environment

CX4121C

  • OEM designation
  • Commonly found in Dell, HPE, and other server platforms
  • Same ConnectX-4 Lx controller
  • Same dual SFP28 port configuration
  • Same PCIe 3.0 x8 interface
  • Same networking capabilities

Shared Hardware Features

  • ConnectX-4 Lx Controller
  • Dual 25GbE SFP28 Ports
  • PCIe 3.0 x8 Interface
  • RoCE Support
  • SR-IOV Support
  • Virtualization Offloads
  • Identical Ethernet Performance

Because OEM manufacturers often relabel the card, systems may identify the adapter as either CX4121A, CX4121C, or MCX4121A depending on firmware and manufacturing origin.


EQUIPMENT COMPATIBILITY

The ConnectX-4 Lx adapter is compatible with systems featuring an available PCIe x8 or x16 slot.

Server Compatibility

Dell PowerEdge

  • R630
  • R640
  • R650
  • R730
  • R740
  • R750

HPE ProLiant

  • DL360 Series
  • DL380 Series
  • Other PCIe-enabled ProLiant Servers

Lenovo ThinkSystem

  • SR630
  • SR650
  • Other PCIe-enabled ThinkSystem Platforms

Cisco UCS

  • C-Series Rack Servers
  • B-Series Blade Servers

Supermicro Servers

  • X10 Series
  • X11 Series
  • X12 Series
  • PCIe-enabled Enterprise Platforms

Switch Compatibility

Compatible with:

  • SFP28 Ethernet Switches
  • 25GbE Infrastructure
  • 10GbE Infrastructure
  • 1GbE Infrastructure
  • DAC Cables
  • SFP28 Optical Transceivers

Virtualization Platforms

  • VMware vSphere
  • Microsoft Hyper-V
  • Proxmox
  • Citrix Hypervisor
  • KVM
  • OpenStack

Important Compatibility Notes

  • Requires compatible SFP28 transceivers or DAC cables.
  • Requires an available PCIe x8 or larger slot.
  • Backward compatible with lower Ethernet speeds when supported by network infrastructure.
  • Low-profile bracket may be installed depending on system configuration.

Included

  • 1x NVIDIA Mellanox ConnectX-4 Lx Network Adapter
  • Model: CX4121A / CX4121C
  • Part Number: MCX4121A-ACAT

Related Part Numbers

  • MCX4121A-ACAT
  • CX4121A
  • CX4121C
  • MCX4121A
  • ConnectX-4 Lx
  • Mellanox ConnectX-4 Lx Dual Port 25GbE
  • Mellanox 25GbE SFP28 NIC