NVIDIA Mellanox MCX512A-ACAT ConnectX-5 EN Network Interface Card: This is a dual-port 25GbE SFP28 Ethernet adapter on a PCIe Gen 3.0 x8 host interface. The card uses the ConnectX-5 EN ASIC and ships with a tall (full-height) bracket. This is an Ethernet-only adapter — not a VPI card and not InfiniBand-capable. This is a refurbished unit tested by T.E.S IT-SOLUTIONS.
Engineering Context
The MCX512A-ACAT is built on the ConnectX-5 EN silicon. The PCIe Gen 3.0 x8 host interface provides up to 64 Gb/s of usable bandwidth, sufficient for 50Gb/s aggregate across both 25GbE ports without saturation. The adapter offloads RDMA over Converged Ethernet (RoCEv1 and RoCEv2), NVMe over Fabrics, and stateless TCP/UDP/IP, freeing host CPU cycles. Each SFP28 port supports 1/10/25GbE auto-negotiation. The card supports SR-IOV with up to 512 virtual functions, ASAP² accelerated Open vSwitch, and VXLAN/NVGRE/GENEVE encap/decap in hardware.
Deployment & Use Cases
Dual-port 25GbE server NIC for hypervisor LACP/MLAG uplinks. Storage initiator into NVMe-oF over RoCEv2 25GbE fabrics. Active-active redundancy across two ToR switches. SR-IOV multi-tenant cloud servers requiring per-VF line-rate. Open vSwitch acceleration via ASAP² for east-west tenant traffic. Container networking offloads in Kubernetes data planes.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX512A-ACAT
Silicon: ConnectX-5 EN
Data Rate: 25GbE per port (1/10/25GbE auto-neg)
Ports: 2x SFP28
Host Interface: PCIe Gen 3.0 x8
Bracket: Tall (full-height)
RDMA: RoCEv1, RoCEv2
Storage Offloads: NVMe-oF target/initiator, T10/DIF
Virtualization: SR-IOV (up to 512 VFs), ASAP² OvS, VXLAN/NVGRE/GENEVE encap/decap
Protocol Support: Ethernet only (EN)
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Compatible with NVIDIA Spectrum series Ethernet switches and any standards-compliant 25GbE Ethernet switch. Works with SFP28 transceivers (SR, LR), SFP28 AOCs, SFP28 DACs, and 1G/10G SFP+ optics in down-negotiated mode. Requires a PCIe Gen 3.0 x8 (or wider) slot — narrower slots will throttle aggregate throughput. This is an Ethernet-only EN card — it does not support InfiniBand. Both ports run independently; no LAG is enforced at the silicon, so bonding/MLAG is configured at the OS or switch layer.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS tests every adapter for ASIC health, both-port link-up at 25GbE, RoCEv2 functional check, and PCIe Gen 3.0 x8 link training. We provide deployment consultation, fast 1-3 day handling, global shipping, and a comprehensive warranty. Visit tes-itsolutions.com for the full enterprise networking catalog.