Mellanox MCX4121A-ACAT ConnectX-4 25GbE Dual-Port SFP28 Network Interface Card

Model: MCX4121A-ACAT (ConnectX-4 Lx)
Ports: 2 × SFP28 (25GbE physical interface)
Speeds Supported: 25GbE, 10GbE, 1GbE per port (auto-negotiated)
Hong Kong Starsurge Group Co., Limited
PCI Express: PCIe 3.0 ×8 host interface
RoCE/ RDMA: Hardware RDMA over Converged Ethernet (RoCE v1/v2) support for low-latency transfers
Virtualization: SR-IOV support (up to 256 virtual functions)
Form Factor: Low-profile PCIe (brackets included in many listings)
Power: Typically under ~7–12 W depending on cables/transceivers
OS Support: Linux, Windows, VMware, FreeBSD (drivers available)