LinksTek
Dual 25Gb/s SFP28 Fiber Port Intelligent RDMA Ethernet Adapter for Virtualization and Storage Servers, Mellanox ConnectX-4 Lx EN MT27711A0 Ethernet Controller, 2X 25GbE PCIE 3.0 x8 NIC Card (CX4121A)
*Price sourced from Amazon.com. Last updated 2026-05-12. Price and availability subject to change.
SpecPicks Verdict
SpecPicks classifies Dual 25Gb/s SFP28 Fiber Port Intelligent RDMA Ethernet Adapter for Vi… as a category leader on buyer feedback in the expansion cards category, based on 18 verified Amazon reviews and our ranking model that weights rating × review-volume × price-fit. LinksTek's positioning sits comfortably above the category median. Use the Compare tool to put it side-by-side with two or three close alternatives before clicking through to Amazon.
Common buyer scenarios for expansion cards of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the Amazon listing before purchase. Prices, stock, and Prime eligibility update directly from Amazon's catalog and may have moved since this page was last verified.
Pros & Cons
Pros
- ✓ Highly rated — 4.9★ average across customer reviews
- ✓ Backed by LinksTek's warranty and support channels
- ✓ Ships via Amazon with Prime eligibility and the standard returns policy
Cons
- ✗ Limited review volume so far — fewer data points on long-term reliability
- ✗ Confirm socket / form-factor / power-rating compatibility against your build before ordering
- ✗ Price, stock, and Prime eligibility update from Amazon and may have changed since this page was last verified
Key Features
- 1. CX4121A is a dual 25GbE SFP28 fiber port intelligent RDMA Ethernet adapter with a PCIE Gen 3.0 x8 interface. Based on the Mellanox ConnectX-4 Lx EN MT27711A0 converged Ethernet controller, it provides a cost-effective and flexible Ethernet solution for Web 2.0, cloud, data analytics, database, and storage platforms.
- 2. Ethernet Controller: Mellanox ConnectX-4 Lx EN MT27711A0；Bus Interface: PCIE 3.0 x8; Ethernet Speed: 2x 25GbE; Connector Type: 2x SFP28 Fiber Ports; Remote Boot: RoCE, PXE, iSCSI; Supports RDMA over RoCE; Support I/O Virtualization and SR-IOV; Support Overlay Networks by providing advanced NVGRE, VXLAN and GENEVE.
- 3. Supports IEEE 802.3by, 25 Gb/s; IEEE 802.3ae 10Gb/s; IEEE 802.3az Energy Efficient Ethernet; IEEE 802.3ap; IEEE 802.3ad; 802.1AX; IEEE 802.1Q; 802.1P VLAN tags and priority; IEEE 802.1Qaz; IEEE 802.1Qbb; IEEE 802.1Qbg; IEEE 1588V2; Support Jumbo frame (9.6KB).
- 4. PCIE Gen 3.0 Standard, 8Gb/s Per Lane. PCIE x8 Interface, 64Gb/s Bandwidth Totally, Ensure 2x SFP28 Fiber Ports archive 25GbE simultaneously. Auto-negotiates to PCIE X8, X4 Lane. Auto-switch to PCIE Gen 3.0, Gen 2.0. Support MSI/MSI-X mechanisms.
- 5. Support plug and play on Windows 11, 10 64bit and Windows Server 2012, 2012R2, 2016, 2019, 2022, 2025 64bit. Compatible with RHEL, CentOS, FreeBSD, VMware and other Linux kernel-based systems.
- 6. Support Open Fabrics Enterprise Distribution (OFED) and Open Fabrics Windows Distribution (WinOF-2). Will compatible with SFP28 transceivers, SFP28 DAC cables and SFP28 AOC cables with PAM4 ethernet links.
Full Specifications
| Brand | LinksTek |
|---|---|
| Unit Count | 1.0 Count |
| 7. ATTENTION | The LinksTek CX4121A serves as a drop-in alternative to the MCX4121A-ACAT for server applications. |
| Model Number | CX4121A |
| Compatibility | Switch, Linux |
| Mfr Part Number | CX4121A |
| Number of Packs | 1 |
| Compatible Devices | Desktop |
| Data Link Protocol | Ethernet |
| Data Transfer Rate | 25000 Megabytes Per Second |
| Hardware Interface | PCI Express 3.0, PCI Express x8 |
| Warranty Description | One Year Warranty. |
| Item Dimensions L x W x H | 4.72"L x 5.91"W x 0.71"H |
| Compatible Operating System Family | Linux, Windows |
Ready to buy?
Dual 25Gb/s SFP28 Fiber Port Intelligent RDMA Ethernet Adapter for Virtualization and Storage Servers, Mellanox ConnectX-4 Lx EN MT27711A0 Ethernet Controller, 2X 25GbE PCIE 3.0 x8 NIC Card (CX4121A) is available on Amazon with Prime shipping and the full Amazon returns policy. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
*Price sourced from Amazon.com. Last updated 2026-05-12. Price and availability subject to change.
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