The Mellanox MCX456A-ECAT (now under NVIDIA branding following the acquisition) is a high-performance ConnectX-4 VPI (Virtual Protocol Interconnect) dual-port network adapter card. It supports both InfiniBand and Ethernet protocols on the same hardware (VPI design), making it versatile for HPC clusters, data centers, storage fabrics, and high-bandwidth enterprise applications.

This card is particularly known for EDR InfiniBand (100 Gb/s) and 100 GbE Ethernet, with excellent low-latency and high-throughput capabilities.

Key Features and Specifications

• Ports: 2 x QSFP28 (supports copper DAC, active optical cables, or transceivers for fiber).

• Data Rates:

◦ InfiniBand: SDR/DDR/QDR/FDR/EDR (up to 100 Gb/s per port, 4x 25.78125 Gb/s lanes with 64b/66b encoding).

◦ Ethernet: 1/10/25/40/50/100 Gb/s (including support for various BASE-R, CR4, SR4, etc., standards).

• Interface: PCIe 3.0 x16 (compatible with PCIe 2.0/1.1; SerDes at 8.0 GT/s; works in x8 or x16 slots).

• Form Factor: Low-profile (half-height) with tall bracket option; dimensions approx. 2.71 in. x 5.6 in. (68.9 mm x 142.24 mm).

• Power Consumption: Typical ~16–19W (passive cables), up to ~22–24W (active cables); max QSFP28 port power 3.5W.

• Environmental: Operating 0°C to 55°C; non-operating -40°C to 70°C; airflow requirements vary (e.g., 400–800 LFM depending on cable type).

• Advanced Features (via ConnectX-4 silicon):

◦ RDMA over Converged Ethernet (RoCE) support.

◦ Hardware offloads for TCP/UDP/IP, stateless offloads, NVMe-oF initiator/target acceleration.

◦ SR-IOV with up to 127 virtual functions.

◦ Low latency, high message rate for MPI/HPC workloads.

◦ Security features like secure boot, encryption offloads.

• Compatibility: Works with Linux, Windows, VMware, and various HPC/OS distributions. Drivers available from NVIDIA (Mellanox OFED or inbox drivers).

This is a ConnectX-4 generation card (not the later ConnectX-5 or newer), released around 2016–2017. It’s widely used in legacy high-performance setups, supercomputing clusters (e.g., for EDR IB fabrics), and 100G Ethernet deployments where dual-port aggregation reaches up to 200 Gb/s theoretical (though PCIe 3.0 x16 caps bidirectional host bandwidth at ~15.75 GB/s or ~126 Gb/s effective, so full dual-port 200 Gb/s isn’t achievable without bottlenecks—common in Gen3-era 100G cards).

It’s distinct from the HPE NVMe-oF 100GbE adapter you asked about earlier (which is likely a customized or rebranded Ethernet-only card, possibly based on similar Mellanox/NVIDIA silicon but optimized for NVMe/TCP or RoCE storage fabrics).

Use Cases

• High-performance computing (HPC) clusters using InfiniBand EDR.

• Low-latency storage (e.g., NVMe-oF over RoCE).

• Virtualization, cloud, big data analytics, AI training (where high bandwidth and RDMA shine).

• Enterprise networking requiring 100G uplinks.

Availability and Notes

These cards are now mostly available refurbished or used on sites like eBay, Amazon, or resellers (prices often $100–$300+ depending on condition). New stock is rare since it’s an older model—NVIDIA has moved to ConnectX-6/7 for 200/400G. Check firmware/drivers on NVIDIA’s networking site for the latest support.

For official details, see the NVIDIA ConnectX-4 user manual and specs:

• https://docs.nvidia.com/networking/display/connectx4ib (or search “NVIDIA ConnectX-4 InfiniBand/Ethernet Adapter Cards”).

If you’re comparing it to the HPE R3B13-80503 / R3B29A (which is a pure 100GbE NVMe-oF-focused card), this Mellanox one offers more flexibility with IB support but may require specific drivers/config for NVMe-oF. Let me know if you need compatibility info for a specific server (e.g., HPE ProLiant, Dell, Supermicro), cabling recommendations, or alternatives like newer ConnectX-6!

The Mellanox MCX456A-ECAT Dual-Port 100GB Network Card is a high-performance wired network card designed for professional use. With two ports and a maximum data rate of 100GB/s, it offers fast and efficient network connectivity for a variety of applications. Compatible with PCIe3.0 X16 ports, this card is ideal for businesses and organizations looking for reliable and high-speed network connections. The Mellanox brand is known for its quality and expertise in the field of networking, making this product a valuable addition to any computer setup.