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Green PCB network card with two SFP cages and gold PCIe edge connector

NVIDIA

NVIDIA MCX4121AACAT ConnectX-4 Lx EN 25GbE 2-port SFP network card

SKU CH-FRP3-7WV4J MPN MCX4121AACAT

Dual-port 25GbE SFP adapter with PCIe 3.0 x8 interface and RoCE low-latency support

  • Interface typePCI Express 3.0 x8
  • Key featuresProduct Type:25Gigabit Ethernet Card
  • Dual 25 GbE ports for high-throughput networking
  • PCI Express 3.0 x8 interface delivers ample host bandwidth
  • Two SFP cages support flexible optical fibre connectivity
  • RoHS-6 and WEEE certified for environmentally responsible deployment
  • Low-latency RoCE and CPU offload accelerate data-intensive workloads

Dual-port 25GbE SFP adapter

The MCX4121AACAT is a ConnectX-4 Lx EN network card that plugs into a PCI Express 3.0 x8 slot and presents two SFP cages for optical-fibre links. It targets servers and workstations that need 10 or 25 Gb/s Ethernet throughput with hardware offloads for transport and application processing.

SFP cages define the media

Two SFP ports let you choose the exact transceiver and fibre type for each link, so reach and cost match the rack layout rather than a fixed copper length. The card itself ships without transceivers or cables, so those must be sourced separately to complete the connection.

Standard half-height plug-in card

The plug-in form factor fits any compatible PCIe 3.0 x8 slot without extra brackets or power cables. Installation fails most often when the SFP modules are mismatched to the fibre or when the host BIOS does not enable the x8 link width.

How it compares

Measured against everything we stock in Ethernet Cards & NICs, at today’s prices. Recalculated every night.

Price $134.99
Pricier than about 59% of the 1,505 comparable items (median $90.99).

Specifications

Product
Brand nameMellanox
Model nameMCX4121A-ACAT
Ports & slots
Interface typePCI Express 3.0 x8
Size & build
Shipping weight4.54 kg
Package size203 × 178 × 51 mm

Questions about this item

How often will the SFP transceivers need replacement under normal use?

The SFP transceivers are separate modules; they only need replacement if a link fails or you change speed, not on a fixed schedule.

What limits sustained throughput on the PCI Express 3.0 x8 interface?

The x8 lane width caps theoretical bandwidth at the 25 Gb/s line rate, so the bus is the first bottleneck under continuous load.

Does the card generate noticeable heat when running 25 GbE all day?

With no onboard fan, the adapter relies on chassis airflow; sustained 25 GbE traffic will warm the heatsink but stays within the RoHS-6 thermal envelope.

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