HPE 817749-B21

640FLR-SFP28 Dual-Port 10/25 GbE FlexibleLOM Network Adapter

The HPE817749-B21 640FLR-SFP28 is a high-performance FlexibleLOM Network Adapter offering two 25 GbE-capableSFP28 ports (auto-negotiating down to 10 GbE). Perfect for ProLiant Gen9 and Gen10 rack and Apollo servers, this card delivers up to 100 Gb/s bi-directional bandwidth per adapter. Engineered for virtualization, cloud workloads, and storage traffic, it accelerates performance while minimizing CPU overhead. With support for overlay tunneling (VXLAN, NVGRE) and RDMA over Converged Ethernet (RoCE), it streamlines overlay networking and offers future-proof scaling. This adapter suits environments needing ultra-fast connectivity and seamless integration with existing fiber infrastructure.

Features

This dual-port SFP28 adapter leverages a Mellanox ConnectX-4 Lx processor and PCIe 3.0 ×8 interface to deliver full line-rate throughput across each port ([turn0search5], [turn0search11]). It supports jumbo frames up to 9.2 KB for efficient large-packet transfers, and includes advanced offload capabilities such as VXLAN/NVGRE tunnel processing and RoCE for reduced latency. Ideal for high-density virtualization and overlay networking, it eases network bottlenecks while providing backward compatibility with existing 10 GbE infrastructure.

Advanced Options

Built for demanding server and virtualization environments, this adapter delivers up to 50 Gb/s per port×and 100 Gb/s total×ensuring high-performance connectivity across workloads. Advanced offload engines like NVGRE tunnel and RDMA boost throughput while preserving CPU resources ([turn0search11]).

Product Key Features

• Dual-port 10/25 GbE SFP28 interface
  

• FlexibleLOM form factor for ProLiant/Apollo servers
  

• Mellanox ConnectX-4 Lx network processor
  

• PCIe 3.0 ×8 host interface
  

• Jumbo frame support up to ~9.2 KB MTU
  

• Offloads: RoCE, VXLAN/NVGRE, TSO/LSO, RSS
  

• Supports SNMP, LLDP, LACP, IPv4/IPv6, MSI-X

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Reliability & Performance

The ConnectX-4 Lx design, jumbo frame capability, and PCIe x8 interface provide consistent low-latency data transfer. At under 10 W of power consumption, it offers high efficiency and thermally optimized performance. Its FlexibleLOM architecture preserves PCIe slots and allows easy upgrades, while broad driver support ensures compatibility with Windows, Linux, VMware, Solaris, and Citrix environments.

Key Features :

• • Dual-port 10/25 GbE over SFP28

  • FlexibleLOM form factor

  • PCIe 3.0 ×8 host interface

  • Mellanox ConnectX-4 Lx processor

  • Jumbo frame support (~9.2 KB MTU)

  • Tunnel offloads: VXLAN, NVGRE

  • RDMA over Converged Ethernet (RoCE, RoCE v2)

  • MSI-X, RSS, TSO/LSO, checksum offload

  • Supports SNMP, LLDP, LACP, IPv4/IPv6

  • Power-efficient (~9.7 W typical)

Specification	Details
Model Number	817749-B21
Product Type	10/25 GbE Dual-Port SFP28 Network Adapter
Form Factor	FlexibleLOM FLR-SFP28
Processor	Mellanox ConnectX-4 Lx (MCX4121A-ACAT)
Bus Interface	PCI Express 3.0 ×8
Ports	2 × 25 GbE over SFP28 (auto-negotiates to 10 GbE)
Data Rate	25 Gb/s per port; 100 Gb/s aggregate
Connector Type	SFP28 duplex
Jumbo Frames	Up to ~9.2 KB MTU
Offload Features	RoCE, VXLAN, NVGRE, TSO/LSO, RSS, checksum, MSI-X
Protocol Support	SNMP, LLDP, VLAN (802.1Q), LACP, IPv6
Power Consumption	~9.7 W operational
Compatibility	HPEProLiant Gen9/Gen10, Apollo Gen9
Operating Temperature	5 °C to 60 °C
Supported OS	Windows Server, Linux, VMware ESXi, Citrix, Solaris