If your Realtek PCIe GbE Family Controller has stopped working, start by checking the Ethernet cable, router port, and whether another device can use the same network. Then check how the adapter appears in Windows and work through troubleshooting steps from least disruptive to most disruptive. The controller is a wired Ethernet adapter—not a Wi-Fi device—and the correct driver can depend on your PC’s manufacturer and exact model.
First identify what is failing
“Realtek PCIe GBE Family Controller no longer works after Windows update,” “Windows has stopped this device,” and “Code 43” describe different reports, not a diagnosis. A cable or router fault, Windows network configuration, a driver issue, or adapter hardware can all interrupt Ethernet.
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- Adapter missing: Check Device Manager to see whether Windows detects the Ethernet controller.
- Adapter listed with a warning or error: Note the exact message or code. The code alone does not establish a Realtek-specific cause.
- Adapter listed without internet: The link, router, network configuration, or ISP may be involved even if the adapter is present.
Also check whether other devices can connect to the same router or network. If they cannot, investigate the shared network before changing this PC.
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1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsCheck the cable, router port, and network
- Make sure the Ethernet cable is firmly connected at both the PC and router.
- Check that the router end is plugged into a LAN/Ethernet port, not the Internet port used for the modem connection.
- If you have another Ethernet cable available, try it.
- Test the same network with another device. If possible, connect this PC to Wi-Fi temporarily; that can restore internet access while you troubleshoot Ethernet.
- If the router or modem may be stuck, restart them. Disconnect power, wait about 30 seconds, reconnect the modem first and let it settle, then reconnect the router. This briefly disconnects everyone using that network.
If another device can connect but this PC cannot, the fault is more likely to be local to the PC, though that does not identify a specific failed part. If other devices also fail, consider the router, modem, or ISP. A USB-to-Ethernet adapter can be used as an optional test with another PC to check the same network; it does not repair the onboard Realtek controller.
#1 Best Overall
- 2.5 Gbps PCIe Network Card: With the 2.5G Base-T Technology, TX201 delivers high-speeds of up to 2.5 Gbps, which is 2.5x faster than typical Gigabit adapters. Performance varies by conditions, distance to devices, and obstacles such as walls
- Versatile Compatibility – The Ethernet Network Adapter is backwards compatible with multiple data rates(2.5 Gbps, 1 Gbps, 100 Mbps Base-T connectivity). The 2.5G Ethernet port automatically negotiates between higher and lower speed connection.
- QoS: Quality of Service technology delivers prioritized performance for gamers and ensures to avoid network congestion for PC gaming
- Wake on LAN – Remotely power on or off your computer with WOL, helps to manage your devices more easily
- Low-Profile and Full-Height Brackets: In addition to the standard bracket, a low-profile bracket is provided for mini tower computer cases
Run Windows network troubleshooting
Windows 11
Start with the automated Network and Internet troubleshooter in the Get Help app, as Microsoft currently recommends for Windows 11. Also open Settings > Network & internet and inspect the Ethernet status.
Windows 10 and Windows 11: reset network components from Command Prompt
If the basic checks do not help, run the following commands in an administrator Command Prompt, in order. Open Start, search for Command Prompt, choose Run as administrator, and confirm the prompt if asked.
Rank #2
- Controller(s)：Realtek RTL8125BG + ASMedia ASM1806.
- Single RJ-45 Port.
- PCIe2.0, x1 Lane.
- Support PXE, VLAN, Jumbo Frames. Not-support WOL, DPDK, iSCSI, FCoE.
- Compatible with Windows 7/8/10/11, Windows Server 2008 R2/2012/2016/2019, Linux 2.6.x to 5.x, Centos 6/7/8, Ubuntu 16/18/19/20, VMware ESXi 6. NOT SUPPORT ESXI 7/8, FREEBSD and HOT SWAPING.
netsh winsock resetnetsh int ip resetipconfig /releaseipconfig /renewipconfig /flushdns
The commands reset Winsock and TCP/IP, release and renew the PC’s IP address, and clear the DNS resolver cache. Check the connection again afterward. Microsoft’s full Ethernet troubleshooting guide covers Windows 10 and Windows 11.
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Restore the driver with the PC maker’s package
If Ethernet still fails—especially if it stopped after an update—get the network driver for your exact PC model from its manufacturer before uninstalling the adapter. The “Realtek PCIe GbE Family Controller” name does not identify one universal driver version suitable for every computer.
Rank #3
- 🚀 Ultra-Fast 2.5G Network Speeds – Upgrade your desktop PC with this 2.5G network card, delivering 2.5Gbps high-speed connectivity, 2.5x faster than traditional Gigabit Ethernet. Ideal for gaming, 4K streaming, large file transfers, and cloud computing, ensuring ultra-low latency and seamless performance.
- 🔄 Universal Compatibility & Easy Setup – This 2.5Gb PCIe network card supports Windows 11/10/8.1/8/7, Linux, and Mac OS. Plug-and-play on Windows 10, with an easy driver download for other systems. Perfect for workstations, gaming rigs, servers, and home networking.
- 🔧 Flexible Installation with Dual Brackets – Designed for various PC setups, this PCIe 2.5Gb network card includes both standard and low-profile brackets, making it compatible with full-size desktops, mini PCs, workstations, and small form-factor computers. Works with PCIe x1, x4, x8, and x16 slots for seamless integration.
- 🔥 Stable & Reliable Performance – Built with an advanced Realtek RTL8125B chip, this 2.5G PCIe Ethernet card ensures efficient data transfer, reduced latency, and a stable network connection. The integrated heat sink improves heat dissipation, ensuring long-lasting durability and uninterrupted performance. Supports Wake on LAN, PXE Boot, and VLAN tagging for advanced networking.
- 💡 Professional Customer Support & Warranty – We offer lifetime technical support to help you with setup, troubleshooting, and performance optimization. If you have any issues, our team will respond within 24 hours to ensure a smooth and reliable networking experience. Enjoy high-speed connectivity with confidence!
- Find the PC manufacturer and exact model. If the Ethernet adapter is on a custom-built desktop, check the motherboard manufacturer’s support page for the board model.
- Download the model-specific network or Ethernet driver from that manufacturer’s support site. If the affected PC is offline, use another PC and transfer the driver on a USB flash drive.
- Open Device Manager, expand Network adapters, right-click the Ethernet adapter, and select Uninstall device. Avoid deleting driver software if Windows offers that as a separate option and you have not saved the replacement package.
- Restart the PC. Windows will look for and install a driver, but it may not restore the correct one automatically.
- If Ethernet remains unavailable, install the OEM driver you saved. Follow the manufacturer’s installation instructions.
Avoid generic driver-download sites and do not assume a Realtek package intended for a different PC will work. If the controller remains undetected after basic checks and the model-specific driver recovery, consult the computer or motherboard maker’s guidance for that model. The available general Windows guidance cannot determine whether a particular system has a firmware setting or hardware fault.
Use Network reset only as a last step
Microsoft says, “Using network reset should be the last step you try.” Network reset removes network adapters and their settings; after the PC restarts, Windows reinstalls the adapters and restores default settings. It can also change saved network profiles to Public. VPN software may need to be reinstalled or configured again, and Hyper-V virtual switches may need to be recreated or reconfigured. Use it only after the less disruptive checks and driver recovery have failed.
Rank #4
- [Super-fast 2.5Gbps Networking] High up to 2.5x-speed with Realtek RTL8125B chip, much faster data-transfer speeds for gaming, living broadcasts and downloads in bandwidth-demanding tasks.
- [Complete Compatibility] Seamless backward compatibility for 2.5Gbps/1Gbps/100Mbps, Support Windows11/10/8.1/8/7, MAC OS and Linux, no dirver needed on Windows10, easily download the driver in Realtek official website for other OS.
- [PCIe to 2.5G RJ45] This 2.5GBASE-T PCIe Network Adater convers a PCIe slot(X1/X4/X8/16) into a 2.5G RJ45 Ethernet Port. Note: Only work with PCIe slot, not for PCI slot.
- [Widely Use with Heat Sink]Comes with standard bracket and low-profile-bracket to meet the needs of different cases such as desktop, workstation, server, mini tower computer and so on. Excellent heat dissipation can reduce the temperature quickly and maintain the stability of network transmission.
- [Customer Service]Friendly service for lifetime technical supporte. If you encounter any problems, please contact us, our customer team will slove the problem for you within 24 hours.
Windows 10 support status
Windows 10 support ended on October 14, 2025. Microsoft says it no longer provides free Windows Update software updates, technical assistance, or security fixes for Windows 10 after that date. Windows 10 PCs continue to work, but Microsoft recommends moving to Windows 11. See Microsoft’s Windows 10 support notice.
Quick Recap
Best Value
- Unparalleled 5 Gbps Speed: Future-proof your desktop PC's wired connection with the 5 Gbps PCIe network card. It takes your connectivity to the next level with speeds 5 times faster than a typical Gigabit PCIe Ethernet card
- Hyper-Fast Internet Access: Experience boosted speed, reduced latency, and enhanced responsiveness with the PCIe network card, making your computer ideal for intense gaming and flawless streaming. Harness your ISP's speeds with added 5GBASE-T technology
- Instant Local Network Transfer: Whether integrated into your client PC or host server, the PCI Express network card establishes lightning-fast connections with other devices in your local network, elevating the efficiency of data transmission
- Crafted for Maximum Reliability: Enhanced with dense fins and high-quality aluminum construction, the PCIe nic optimizes heat dissipation, ensuring consistent performance and reliability
- Supports Windows 11 / 10 / Windows Server 2022: Simply install the driver from the included disc or download it from our website to achieve the full 5Gbps speed. Supports Wake on LAN and QoS
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