Identity & Definition
This enterprise Ethernet network interface card, the HPE 817751-001 (640SFP28), is a dual-port 10/25GbE Ethernet adapter in HPE OEM form factor based on the Mellanox ConnectX-4 Lx ASIC with two SFP28 connectors. This is an Ethernet-only adapter — it does not support InfiniBand. This is the HPE OEM version, functionally equivalent to Mellanox MCX4121A-ACAT. Condition: Refurbished — tested by T.E.S IT-SOLUTIONS.
Engineering Context
The HPE 640SFP28 (817751-001) uses ConnectX-4 Lx silicon providing dual-port 25GbE or 10GbE Ethernet with hardware offloads for VXLAN/NVGRE overlay networks, RoCE v2 RDMA, SR-IOV (up to 64 VFs per port), and stateless offloads (checksum, LSO, LRO). Each SFP28 port supports 25GbE natively and auto-negotiates to 10GbE with SFP+ optics. The ConnectX-4 Lx is the "lite" version of ConnectX-4 — Ethernet only, reduced feature set compared to the full ConnectX-4. HPE Spare P/N: 817753-B21. Commonly found in ProLiant Gen9/Gen10 configurations.
Deployment & Use Cases
HPE ProLiant Gen9/Gen10 server upgrades from 10GbE to 25GbE without replacing switches (SFP28 backward-compatible with SFP+ 10GbE). Virtualized VMware ESXi and Hyper-V environments requiring SR-IOV for direct VM-to-NIC passthrough. iSCSI or NFS storage connectivity at 25GbE with RoCE v2 RDMA support. General-purpose 10/25GbE server connectivity in enterprise data centers.
Technical Specifications
OEM: HPE (Mellanox ConnectX-4 Lx)
HPE P/N: 817751-001
HPE Spare: 817753-B21
Equivalent: Mellanox MCX4121A-ACAT
ASIC: ConnectX-4 Lx
Speed: 10GbE / 25GbE per port
Ports: 2x SFP28
Host Interface: PCIe 3.0 x8
RDMA: RoCE v2
SR-IOV: Up to 64 VFs per port
Condition: Refurbished
Compatibility & Hard Constraints
Ethernet Only: ConnectX-4 Lx does not support InfiniBand. For InfiniBand, use ConnectX-4 VPI or later. SFP28 Ports: Native 25GbE. Backward-compatible with 10GbE SFP+ optics/DACs. Not compatible with QSFP28 or QSFP-DD. PCIe 3.0 x8: Requires physical x8 slot minimum. PCIe 2.0 compatible at reduced bandwidth. HPE OEM: Functionally identical to MCX4121A-ACAT. Uses standard Mellanox firmware and MLNX_OFED or inbox drivers. HPE firmware updates via HPE SPP. Not 50/100GbE: ConnectX-4 Lx supports maximum 25GbE per port. For 50/100GbE, ConnectX-5 or later required. 25GbE Requires 25GbE Switch: Both adapter and switch must support 25GbE for 25G operation. With 10GbE switches, ports operate at 10GbE. Predecessor: ConnectX-3 Pro 10GbE. Successor: ConnectX-5 25/50GbE (MCX512A).
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS validates every adapter for full PCIe link training, dual-port initialization, and link negotiation at both 10GbE and 25GbE before shipment. Technical consultation available for server compatibility verification. Global shipping with tracking. 1–3 business day handling.