To change your LAN speed from 100 Mbps to 1000 Mbps (1 Gbps) on Windows 10, open Device Manager, expand Network adapters, right-click your Ethernet adapter, choose Properties, and on the Advanced tab set Speed & Duplex to Auto Negotiation or 1.0 Gbps Full Duplex. A gigabit link also needs a gigabit port on your router or switch and a working Cat5e or better cable; a bad cable is the most common reason a connection is stuck at 100 Mbps.
Windows 10 reached end of support on October 14, 2025. Consumer Extended Security Updates (ESU) now run until October 12, 2027.
Quick Answer
Device Manager > Network adapters > Ethernet adapter > Properties > Advanced > Speed & Duplex > Auto Negotiation (or 1.0 Gbps Full Duplex).
Check Your Current Speed
Open Settings > Network & Internet > Status > View hardware and connection properties (or Change adapter options > right-click Ethernet > Status). Link speed shows 100/100 (Mbps) or 1000/1000 (Mbps).
Change the Adapter Setting
- Right-click Start and open Device Manager.
- Expand Network adapters, right-click the Ethernet adapter, and choose Properties.
- Open the Advanced tab and select Speed & Duplex (sometimes Link Speed).
- Choose Auto Negotiation. If it still links at 100, try 1.0 Gbps Full Duplex.
- Click OK. The connection drops for a moment.
Why It’s Stuck at 100 Mbps
| Cause | Fix |
|---|---|
| Damaged or old cable (Cat5, or broken wires) | Replace with Cat5e, Cat6 or better |
| Router or switch port is 100 Mbps only | Use a gigabit port or device |
| Energy-saving settings | Turn off Green Ethernet / Energy Efficient Ethernet on the Advanced tab |
| Outdated driver | Update through Windows Update or the PC maker’s site |
| Adapter only supports 100 Mbps | Use a gigabit USB adapter |
For wireless devices, you may need your Wi-Fi password.
Troubleshooting
- No connection after forcing 1 Gbps: The other end can’t do gigabit. Set it back to Auto Negotiation.
- Internet speed still slow: Your internet plan may be slower than your LAN. Link speed only limits local traffic.
- Need your adapter’s address? See finding your MAC address.
Frequently Asked Questions
Will this make my internet faster?
Only if your internet plan is faster than 100 Mbps.
What cable do I need?
Cat5e or better for gigabit. Cat6 is a safe choice.
Summary
- Check link speed in network status.
- Set Speed & Duplex to Auto Negotiation.
- Replace the cable if it stays at 100.
- Check the router port and driver.
Kermit Matthews is a freelance writer based in Philadelphia, Pennsylvania with more than a decade of experience writing technology guides. He has a Bachelor’s and Master’s degree in Computer Science and has spent much of his professional career in IT management.
He specializes in writing content about iPhones, Android devices, Microsoft Office, and many other popular applications and devices.