HP 331FLR Network Adapter 629135-B21 - Quad 1Gb Flex LOM

In this review the HP 331FLR Network Adapter 629135-B21 is assessed as a compact, high-density Ethernet option for data centers running select HP ProLiant Gen8 rack servers. The bottom line: it is for administrators who need consistent line-rate 1 Gb performance across four ports while keeping power draw low. Tested in virtualized and consolidated server environments, the adapter delivers predictable throughput and a small footprint, making it a practical choice when maximum port density and efficient power use matter more than 10 Gb uplinks.

Key Features

• Quad 1 Gb ports: Provides four full line-rate Ethernet ports, enabling up to 4 Gb aggregate throughput for bandwidth-hungry virtualized workloads.
• Flexible LOM form factor: The Flex LOM design integrates into compatible HP ProLiant Gen8 servers to free up PCIe slots and simplify server networking.
• Low power consumption: Single-chip implementation reduces power draw for four ports compared with multiple discrete controllers, helping lower server power budgets.
• PCI Express 2.0 x4 interface: Uses a PCIe 2.0 x4 bus interface to connect to the host with sufficient lanes for consistent 1 Gb performance per port.
• High port density: Small physical dimensions allow dense networking in rack servers where space is at a premium.

Who It's For

The HP 331FLR is aimed at IT teams running select HP ProLiant Gen8 rack servers who prioritize port density and predictable 1 Gb performance for virtualization, server consolidation, or network segmentation tasks. It is a good fit where multiple 1 Gb endpoints must be provided from a single server slot without adding significant power or heat.

Those who need faster uplinks such as 10 Gb or 25 Gb, or who are working with non-HP Gen8 platforms, should look elsewhere. The adapter is specialized for compatible HP server hardware and for environments that can make use of four dedicated 1 Gb ports rather than fewer higher-speed links.

Pros & Cons

Pros

• Delivers full line-rate across four 1 Gb ports, useful for steady aggregate throughput up to 4 Gb.
• Flexible LOM form factor preserves PCIe slots and simplifies integration in supported HP ProLiant Gen8 servers.
• Single-chip design reduces power consumption compared with multiple-controller solutions.

Cons

• Limited to 1 Gb per port, so it is not suitable where 10 Gb or faster links are required.
• Compatibility is tied to select HP ProLiant Gen8 rack servers, limiting cross-platform use.

Specifications

Product	HP Ethernet 1Gb 4-port 331FLR
Brand	HP
Ports	4 x 1 Gb Ethernet
Interface (Bus)	PCI Express 2.0 x4
Form Factor	Flex LOM (LOM)
Dimensions (WxDxH)	11.8 cm x 7.6 cm
Designed For	Select HP ProLiant Gen8 rack servers

Our Verdict

The HP 331FLR is a practical, value-conscious network adapter for organizations that need reliable 1 Gb connectivity at high port density inside supported HP ProLiant Gen8 servers. It stands out for low power use and predictable line-rate performance across four ports, making it a sensible buy when 1 Gb per port meets workload requirements and broader compatibility is not needed.

Frequently Asked Questions

Is this adapter compatible with non-HP servers?
The 331FLR is designed for select HP ProLiant Gen8 rack servers and may not be supported or physically compatible with non-HP platforms.

What is the maximum aggregate throughput?
The card provides four 1 Gb ports for a total aggregate throughput up to 4 Gb under full line-rate conditions.

Does it reduce power consumption?
Yes, the single-chip, quad-port design aims to lower power requirements compared with multiple discrete controllers for equivalent port counts.