Does it support RDMA and RoCE?

Yes, RoCE v2, which keeps latency low and CPU usage down for storage traffic on a properly configured switch fabric.

What cabling does it need?

SFP28 direct-attach copper for in-rack runs, or SFP28 SR optics with OM4 fibre for distance. Order the cable or optic with the card.

Yes. The ports negotiate down to 10GbE with SFP+ cables or optics, so the card works in a 10G environment today and moves to 25G later.

MCX4121A-ACAT - Mellanox 2-Port 25Gbs SFP28 PCIE 3.0 Network Card

Name: MCX4121A-ACAT - Mellanox 2-Port 25Gbs SFP28 PCIE 3.0 Network Card
Brand: Mellanox
SKU: MCX4121A-ACAT
Price: 120 USD
Availability: InStock

MCX4121A-ACAT - Mellanox 2-Port 25Gbs SFP28 PCIE 3.0 Network Card | US IT Hardware

Product overview

The Mellanox ConnectX-4 Lx EN MCX4121A-ACAT is a dual-port 25GbE network adapter, the mainstream upgrade path from 10G that has become the default server NIC for modern storage and virtualization. It runs up to 25GbE per port over SFP28 on PCIe Gen3 x8, with RoCE v2 for low-latency RDMA, and it also links at 10G with SFP+ where needed. Excellent price-to-performance for east-west traffic.

Expedited and overnight shipping options are available at checkout, priced by destination and service.
Purchase orders accepted from qualified institutions.
Refunds within 14 days and replacements within 30 days of delivery with an RMA (25% restocking fee on customer-initiated returns), and every part carries our Standard 30-Day Warranty - see our return policy or contact US IT Hardware.

Technical Information

Manufacturer part #	MCX4121A-ACAT
Brand	Mellanox
Condition	Refurbished
Length	7.6 Inches
Card Height	Low-profile
Product Line	ConnectX-4 Lx
Product Type	Gigabit Ethernet Card
Compliance Standards	RoHS, WEEE
Type of Expansion Slots	SFP28
Maximum Data Transfer Rate	25
Remote Management Protocol	RMON 2, RMON
Quantity of Ethernet LAN Ports (RJ-45/SFP/SFP+)	2

Interfaces/Ports

Ports	2x 25GbE (also 10GbE)
Protocol	Ethernet (EN)
Connector	SFP28
Host Interface	PCI Express 3.0 x8
Media Standard	Optical Fiber

Management & Protocols

Offloads	RoCE v2

Physical Characteristics

Form Factor	Plug-in Card

Condition

New and recertified.

Good to know

OEM vs generic: Mellanox/NVIDIA-branded part. We confirm whether a generic-coded SFP28 will link on your switch.
What it needs to link: SFP28 DAC for in-rack, or SFP28 SR optics with OM4 fibre for distance. It also links at 10G with SFP+ where needed. Order the cable or optic with the card.

Frequently asked questions

Which servers and slots fit it?

PCIe Gen3 x8; confirm by model. Send us your server model and we will confirm fit before you order.

Mellanox 2-Port 25Gbs SFP28 PCIE 3.0 Network Card