Mellanox ConnectX-4 Lx Dual Port 25GbE NIC Adapter
Best high-speed adapter for demanding enterprise data center environments.
The Mellanox ConnectX-4 Lx EN Adapter Card delivers robust 25GbE networking for demanding environments. It features a PCI Express 3.0 x8 interface and dual SFP ports for optical fiber connections. This card excels with low-latency RDMA over Converged Ethernet (RoCE) and offers hardware offloads for virtualization technologies like NVGRE and VXLAN. Enhanced with Multi-Host support, end-to-end QoS, and congestion control, it ensures efficient data transport. The adapter adheres to RoHS-6 and WEEE environmental standards, making it a reliable choice for high-performance networking solutions.
$70.00
More ConnectX Options
Owner Satisfaction
4.7
/ 5
Category Rank
14
/ 961
#14 in Network Cards & Adapters
Price vs Category Average
-93%
Below average
Host Interface
3.08
/ PCI Express x
Who it's for
- Data scientists and engineers running high-throughput AI or storage workloads
- System architects needing minimal CPU overhead for real-time data processing
- Budget-conscious IT managers seeking high-speed connectivity without premium enterprise costs
Who should skip it
- Small businesses lacking the budget for a full network infrastructure overhaul
- Advanced network engineers requiring specialized hardware offloads for complex virtualization
- Data center operators managing servers with strict power and cooling limitations
Performance breakdown
Data Throughput
Delivers consistent 25GbE speeds for demanding high-bandwidth enterprise workloads.
Latency Performance
RoCE support ensures minimal delay for time-sensitive data packet delivery.
CPU Offloading
Hardware acceleration significantly reduces host processor strain during heavy network traffic.
Virtualization Efficiency
Advanced SR-IOV and tunneling support streamline complex virtualized network environments.
Connectivity Versatility
Flexible speed support handles legacy 1GbE alongside modern 25GbE infrastructure.
Multi-Host Scalability
Multi-Host technology allows efficient resource sharing across independent server nodes.
Key Specs
Host Interface
PCI Express 3.0 x8
Total Number of Ports
2
Expansion Slot Type
SFP
Media Type Supported
Optical Fiber
Form Factor
Plug-in Card
Maximum Data Rate
25 Gbps
Environmental Certification
RoHS-6, WEEE
Model Number
MCX4121A-ACAT
Features
- High-speed 25GbE connectivity
- Low latency RoCE for fast data transfer
- Offloads network tasks from the CPU
- Hardware acceleration for virtualization
- Supports multiple independent hosts
- Provides QoS and congestion control
- Flexible speed support (1/10/25Gb/s)
- Hardware-based I/O virtualization
What customers say
The Mellanox ConnectX-4 Lx adapter earns strong praise for delivering exceptional value and performance in data center upgrades. Users value it as a cost-effective bridge from 10GbE, avoiding the high cost of 100GbE solutions. The core positive feedback centers on its ultra-low latency, which is crucial for demanding workloads like virtualization and high-speed storage fabrics. Once installed, customers report reliable, set-it-and-forget-it operation, supported by mature driver stability across major operating systems. While initial setup can present minor complexity for novices regarding firmware and transceiver compatibility, professionals view this adapter as an industry workhorse. It solidifies its reputation by offering unparalleled speed and efficiency in the 25GbE segment.
Know before you buy
Yes, the ConnectX-4 Lx is flexible and supports 1Gb/s, 10Gb/s, and 25Gb/s connection speeds, allowing you to scale your network infrastructure as your needs evolve.
This card uses SFP28 ports designed for optical fiber connections. You will need compatible SFP28 transceivers or Direct Attach Copper (DAC) cables to connect to your switch.
By handling virtualization tasks like NVGRE, VXLAN, and GENEVE directly on the card, the adapter reduces the processing burden on your server's CPU. This frees up computing resources for your applications, resulting in better overall system efficiency.
Absolutely. The card supports SR-IOV, which allows for hardware-based I/O virtualization. This enables virtual machines to access the network adapter directly, significantly improving performance and reducing latency in virtualized setups.
RoCE (RDMA over Converged Ethernet) allows data to be transferred directly between the memory of two servers without involving the operating system or CPU. This results in extremely low latency and high throughput, which is critical for high-performance computing and storage-heavy workloads.
Multi-Host technology allows a single adapter to be connected to multiple independent host servers simultaneously. This is particularly useful for high-density server configurations where you want to consolidate network connectivity while maintaining isolation between hosts.
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