The Atheros AR8131 PCI E Gigabit Ethernet Controller (NDIS 6.20) driver allows Windows to communicate with your computer’s built-in wired network adapter. Installing a compatible driver can help restore Ethernet connectivity when the controller is unrecognized, appears with a warning in Device Manager, or stops working after a system change.

Key Features

• Wired network connectivity: Enables the Atheros controller to connect to a router, switch, or modem through an Ethernet cable.
• Gigabit Ethernet support: Supports the adapter’s gigabit networking capability when used with compatible network equipment and cabling. Actual transfer speeds depend on your connection and hardware.
• Windows network integration: Provides the interface Windows needs to detect and manage the adapter, including its network status and available configuration options.
• Troubleshooting support: Reinstalling a suitable driver may resolve issues caused by missing or damaged driver files, though it will not fix faulty cables or hardware.

How to Install

1. Confirm the adapter model. Open Device Manager and look under Network adapters for the Atheros AR8131 PCI E Gigabit Ethernet Controller (NDIS 6.20). If it appears as an unknown Ethernet controller under Other devices, check its hardware IDs in Properties to confirm a match.

1. Check Windows compatibility. Identify whether your PC runs Windows 11, Windows 10, Windows 8, or Windows 7, and check its system architecture. Choose a package explicitly compatible with your configuration; the NDIS 6.20 label alone does not establish support for every Windows version listed.

1. Download and extract the driver. Save the matching package to your computer and extract it if necessary. If Ethernet is unavailable, use another connection or transfer the download from a different computer using a USB drive.

1. Install the package. Run the included installer, if provided, and follow its prompts. For a driver-only package, right-click the controller in Device Manager, select Update driver, choose Browse my computer for drivers, and point Windows to the extracted folder.

1. Restart and test the connection. Restart if prompted, connect your Ethernet cable, and confirm that the adapter appears without a warning icon. If installation fails or connectivity worsens, use Roll Back Driver when available and check for a compatible package from your computer or motherboard manufacturer.

Common Issues and Fixes

• Install fails or rolls back: Confirm the package matches Windows version and 32/64-bit architecture, run setup as administrator, and use a signed Atheros/ODM driver. For the AR8131 NDIS 6.20 controller, avoid generic Realtek packages.
• Device not detected: Check the PCIe slot/BIOS, reseat the card, and open Device Manager > View > Show hidden devices. Look under Network adapters or Other devices for an unknown Ethernet controller; install the driver manually via Update driver > Browse.
• Version conflicts or link drops: Uninstall any existing Atheros/Qualcomm Ethernet driver and select “Delete the driver software,” reboot, then install the correct NDIS 6.20 package. If Windows Update replaces it, roll back to the stable OEM version.