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Green low-profile PCIe card with two SFP28 cages and a silver bracket

NVIDIA

NVIDIA ConnectX-5 EN MCX512A-ACAT 25GbE dual SFP28 network card

SKU CH-XC86-EDJFP MPN MCX512A-ACAT

Dual-port 25 Gb/s Ethernet adapter with SFP28 connectors, PCIe 3.0 x8, and sub-600 ns latency

  • Rated speedData Rate: 1/10/25 Gb/s Ethernet
  • Connection typesDual SFP28 Ethernet (copper and optical)
  • Humidity rangeOperational: 10% to 85% relative humidity Non-operational: 1
  • Seller noticeREGULATORY Safety: CB / cTUVus / CE EMC: CE / FCC / VCCI / I
  • Key featuresPROTOCOL SUPPORT Ethernet: 25GBASE-CR/CR-S, 25GBASE-SR, 25GB
  • Product dimensionsSize: 2.71 in × 5.6 in (68.9 mm × 142.24 mm) - low profile
  • Dual-port 25 GbE throughput with SFP28 flexibility
  • PCIe 3.0 x8 interface at 8.0 GT/s for high bandwidth
  • Sub-600 ns latency accelerates HPC and storage workloads
  • SR-IOV and NFV offloads isolate VMs and cut CPU load
  • Low-profile 68.90 mm x 142.24 mm fits dense servers

Dual 25GbE SFP28 connectivity

The ConnectX-5 EN MCX512A-ACAT provides two SFP28 ports operating at 1, 10 or 25 Gb/s Ethernet over copper or optical media. A PCI Express 3.0 x8 host interface and OCP 2.0 low-profile bracket fit standard server chassis. Hardware offloads for VXLAN, NVGRE, MPLS, GENEVE and NSH reduce CPU overhead in virtualised and containerised workloads.

Sustained throughput with sub-600ns latency

The adapter maintains low sub-600ns latency and high message rates under continuous load, supported by stateless offloads for inner-packet processing and header rewrite. SR-IOV isolates virtual-machine traffic with dedicated adapter resources, while NVMe over Fabric offloads and Dynamic Connected Transport keep storage and compute pipelines moving without CPU intervention during prolonged transfers.

Upgrade from single-port or 10GbE adapters

Replacing a single-port 10GbE NIC doubles port density and raises the ceiling to 25GbE for storage clusters, machine-learning nodes or high-performance-computing fabrics. The jump is worthwhile when the server backplane and switch fabric already carry 25GbE lanes and the workload demands hardware-offloaded overlay networks or NVMe-oF target offload.

How it compares

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

Price $413.99
Pricier than about 84% of the 1,505 comparable items (median $90.99).

Specifications

Product
Brand nameNVIDIA
Model nameConnectX-5
Part numberMCX512A-ACAT
Performance
Rated speedData Rate: 1/10/25 Gb/s Ethernet
Ports & slots
Connection typesDual SFP28 Ethernet (copper and optical)
Size & build
Product dimensionsSize: 2.71 in × 5.6 in (68.9 mm × 142.24 mm) - low profile
Shipping weight0.91 kg
Package size203 × 178 × 51 mm
Environment & compliance
Humidity rangeOperational: 10% to 85% relative humidity
Non-operational: 10% to 90% relative humidity

Questions about this item

How much heat does the ConnectX-5 EN MCX512A-ACAT add when running 25 GbE traffic all day?

The card is a passive, low-profile plug-in design with no onboard fan; heat dissipation depends on your server chassis airflow and the thermal budget of the PCIe 3.0 x8 slot it occupies.

Which transceivers or direct-attach cables must I already own to use the dual SFP28 ports?

Each port accepts SFP28 modules or DACs rated for 25GBASE-SR, 25GBASE-LR, 25GBASE-CR/CR-S, 10GBASE-SR, 10GBASE-LR, 10GBASE-ER or 1000BASE-X, so you need compatible optics or copper cables for the speeds you plan to run.

Will the PCIe 3.0 x8 interface bottleneck the card if I install it in an older server that only has PCIe 2.0 slots?

The adapter requires a PCIe 3.0 x8 slot (8.0 GT/s SERDES) for full 25 Gb/s line rate; a PCIe 2.0 slot halves the bus bandwidth and will limit throughput accordingly.

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