RTL8125B
PCIe to 2.5 Gigabit Ethernet controller for internal network cards
Product Overview
Description
The Realtek RTL8125B is a PCIe to 2.5 Gigabit Ethernet controller designed for internal network interface cards and motherboard integration.
This controller provides 2.5x the bandwidth of Gigabit Ethernet through PCIe interface, ideal for high-performance desktop and server applications.
RTL8125B supports PCIe 2.1 and is backward compatible with 10/100/1000Mbps networks for seamless integration.
Product Series
RTL
Primary Application
Desktop motherboards
Key Features
- 2.5 Gigabit Ethernet over PCIe
- PCIe 2.1 interface
- Backward compatible with 1GbE
- Auto-negotiation support
- Jumbo frame support
- Low power consumption
- Wake-on-LAN support
- VLAN tagging support
Specifications
| Interface | PCI Express 2.1 |
|---|---|
| Speed | 10/100/1000/2500Mbps |
| Auto-Negotiation | Yes |
| Wake-on-LAN | Supported |
| VLAN | 802.1Q |
| Jumbo Frame | Up to 9KB |
| Power Consumption | <1.5W active |
| Operating Temperature | 0°C to +70°C |
| Package | QFN-48 |
| ESD Protection | 4kV contact, 8kV air |
Applications
Desktop motherboards
Electronic system design
Server network cards
Communication and interface
Workstations
Electronic system design
Gaming systems
Electronic system design
High-performance PCs
Electronic system design
FAE Expert Insights
"RTL8125B is becoming the standard for 2.5GbE on modern motherboards. The PCIe interface provides better performance than USB solutions for internal applications. We recommend this for new motherboard designs and high-performance NICs."
Standard 2.5GbE solution for motherboard integration
— David Liu, BeiLuo
Frequently Asked Questions
What is the difference between RTL8125B and RTL8156B?
RTL8125B uses PCIe interface for internal applications like motherboards. RTL8156B uses USB 3.0 for external dongles and docking stations. Both offer 2.5GbE performance.
RTL8125B for internal/motherboard. RTL8156B for external/USB applications.
Does RTL8125B require additional drivers?
RTL8125B drivers are built into Windows 10 version 2004 and later. Linux kernel 5.x+ includes native support. Drivers available for older systems.
Native support in modern Windows. Check OS version for compatibility.
Can RTL8125B be used in servers?
Yes, RTL8125B is suitable for servers and workstations. For enterprise servers requiring advanced features, consider Intel alternatives.
Suitable for standard servers. Consider enterprise-grade alternatives for critical applications.
What PCIe lane configuration does RTL8125B need?
RTL8125B uses PCIe x1 lane. It can operate in x1 slots or larger slots (x4, x8, x16) with appropriate mechanical compatibility.
Works in any PCIe slot. x1 sufficient for 2.5GbE bandwidth.
Is RTL8125B compatible with existing Gigabit switches?
RTL8125B auto-negotiates down to 1Gbps when connected to Gigabit switches. Full 2.5GbE speed requires multi-gigabit capable switches.
Backward compatible. Upgrade switch infrastructure for full 2.5GbE performance.