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.
