Network adapter HP Ethernet 1Gb 4-port 331FLR, 4x 1 Gbps ports, FLR form factor

The HP Ethernet 1Gb 4-port 331FLR is a server network adapter that provides four 1 Gbps Ethernet ports in an FLR (FlexibleLOM/FLR) form factor for select HP ProLiant Gen8 and Gen9 rack servers. Implemented as a single-chip solution, the adapter delivers full line-rate performance across all ports while maintaining low power consumption. It supports virtualization and advanced offload features to optimize network stack performance and can serve as a platform for future upgrades to higher-speed networking.

Advantages

The 331FLR offers multi-port density in a FlexibleLOM form factor suitable for rack server use. It provides full duplex 1 Gbps throughput on each port with a combined aggregate bandwidth of 4 Gbps, and includes hardware offload functions such as Large Send/Receive Offload, TCP checksum and segmentation offload, and support for jumbo frames to reduce CPU overhead. The adapter supports virtualization technologies and MSI-X to improve interrupt handling, and includes IEEE 1588 support for precise timing. Integration with HP Sea of Sensors 3D helps regulate power and thermal behavior for efficient operation.

Suitable for

• Virtualization hosts and VM-dense servers
• Network segmentation and multi-homing in data centers
• Server consolidation and hypervisor deployments
• Storage access and general server connectivity

Key specifications

• Form factor: FlexibleLOM / FLR designed for compatible rack servers
• Ports: 4 × 1 Gbps Ethernet ports (full duplex)
• Aggregate throughput: up to 4 Gbps total across all ports
• Offload features: Large Send/Receive Offload, TCP checksum and segmentation offload
• Frame support: Jumbo frames support
• Interrupt and virtualization support: MSI-X, VMware NetQueue and Microsoft VMQ support
• Timing: IEEE 1588 (Precision Time Protocol) support
• Power and thermal integration: Support for HP Sea of Sensors 3D technology

How to use

Install the adapter into a compatible FLR slot on supported HP ProLiant Gen8 or Gen9 rack servers following the server hardware installation guide. Connect standard Cat5e/Cat6 Ethernet cabling to the four RJ45 ports and configure link settings in the server BIOS/UEFI or operating system network configuration. Install or update the appropriate HP network drivers and firmware for the operating system or hypervisor in use to enable offload and virtualization features. Configure VLANs, teaming, or other network policies as required for your environment.

Usage recommendations

For optimal performance, use quality Ethernet cabling (Cat5e or higher), keep firmware and drivers up to date, and configure offload and virtualization features according to workload needs. When deploying in virtualized environments, enable supported VM offload features (VMQ/NetQueue) and consider link aggregation or port teaming for redundancy and increased throughput.