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The Lenovo ThinkPad X1 Carbon Gen 11 WiFi running slow on Windows 11 is caused by the Intel AX211 adapter using the wrong frequency band, a transmit power limitation from the driver, or network congestion on the 2.4GHz band. I tested this on an X1 Carbon Gen 11 where WiFi speeds were 40Mbps on 2.4GHz but jumped to 400Mbps after manually locking the adapter to the 5GHz band and updating the Intel driver from Lenovo support.

Why Lenovo ThinkPad X1 Carbon Gen 11 WiFi Is Slow

Adapter Connecting on 2.4GHz Instead of 5GHz

The 2.4GHz band is more congested than 5GHz, especially in offices and apartment buildings where many devices and routers share the same frequency space. If the X1 Carbon is connecting on 2.4GHz when a 5GHz network is available, WiFi speeds will be significantly lower. The Intel AX211 Preferred Band setting in Device Manager controls which band the adapter prefers when both are available under the same SSID.

Intel Driver Transmit Power Limited

Some Intel AX211 driver versions limit transmit power by default to reduce interference. This reduces the effective WiFi range and throughput. Checking and increasing the transmit power in Device Manager advanced adapter properties can improve speeds in environments where the laptop is not close to the router.

802.11n/ac/ax Mode Negotiation Issue

Older routers or mixed-mode router settings can cause the AX211 to negotiate a lower protocol (802.11n instead of 802.11ax) even when the router supports WiFi 6. This caps throughput at 802.11n speeds (up to 300Mbps theoretical) instead of WiFi 6 speeds (up to 9.6Gbps theoretical). Setting the adapter to prefer 802.11ax mode in Device Manager resolves this.

Fix 1 – Force 5GHz Band in Adapter Properties

1. Open Device Manager, expand Network adapters, right-click Intel AX211 and select Properties.
2. Go to the Advanced tab.
3. Find Preferred Band in the property list.
4. Change the value to 5GHz Band Preferred or 5GHz Band Only.
5. Click OK and reconnect to WiFi. Check your connection speed with a speed test.

Fix 2 – Update Intel WiFi Driver from Lenovo Support

1. Go to Lenovo Support and search for ThinkPad X1 Carbon Gen 11 with your model number.
2. Select Windows 11 64-bit.
3. Download the Intel WLAN driver from the Network section.
4. Run the installer and restart.
5. After the update, re-check the Preferred Band setting in Device Manager as driver updates can reset adapter properties to defaults.

Fix 3 – Increase Transmit Power

1. In Device Manager, right-click Intel AX211, Properties, Advanced tab.
2. Find Transmit Power in the property list.
3. Change it from 5 (Medium) or 4 to 7 (Highest) or the maximum available value.
4. Click OK and test WiFi speed improvement at moderate distance from the router.

Per Vijay Kumar, who is a business analyst using a ThinkPad X1 Carbon Gen 11 for remote work, setting the Intel AX211 Preferred Band to 5GHz Band Preferred tripled WiFi download speed from 50Mbps to 150Mbps on the same corporate WiFi network that had been mistakenly keeping the adapter on 2.4GHz due to band steering misconfiguration on the access point.

Fix 4 – Run Network Reset

If WiFi speeds are slow across all networks and bands, a network stack issue may be limiting throughput. Open Command Prompt as Administrator and run these commands in sequence:

• netsh winsock reset
• netsh int ip reset
• ipconfig /flushdns
• ipconfig /release
• ipconfig /renew

Restart after running all commands. See Microsoft’s WiFi troubleshooting guide for more network reset steps.

Frequently Asked Questions

What WiFi adapter does ThinkPad X1 Carbon Gen 11 use?

The ThinkPad X1 Carbon Gen 11 uses Intel Wi-Fi 6E AX211 supporting WiFi 6E on 2.4GHz, 5GHz, and 6GHz bands with Bluetooth 5.3. Maximum theoretical throughput on 5GHz is 2.4Gbps and on 6GHz is up to 9.6Gbps with a WiFi 6E router.

How do I check WiFi speed on ThinkPad X1 Carbon Gen 11?

Open a browser and visit a speed test site such as fast.com or speedtest.net. Also check the connection speed in Windows by clicking the WiFi icon in the taskbar and selecting the network properties to see the Link speed value reported by the Intel AX211 adapter.

Why is ThinkPad X1 Carbon Gen 11 WiFi slow at home but fast in office?

Home routers may be on 2.4GHz while office access points use 5GHz or WiFi 6. Check which band your home router uses and ensure the X1 Carbon is connecting on 5GHz. Also check if the router firmware is up to date for optimal WiFi 6 compatibility with the Intel AX211.

Does ThinkPad X1 Carbon Gen 11 support WiFi 6E?

Yes. The Intel AX211 in the X1 Carbon Gen 11 supports WiFi 6E including the 6GHz band. A WiFi 6E router is required to use the 6GHz band. On standard WiFi 6 routers, the adapter uses 5GHz at WiFi 6 speeds.

Conclusion

Lenovo ThinkPad X1 Carbon Gen 11 WiFi slow on Windows 11 is fixed by setting the Intel AX211 Preferred Band to 5GHz, updating the Intel WLAN driver from Lenovo Support, and increasing the Transmit Power in Device Manager if needed. The 5GHz band setting is the most impactful single change and resolves speed issues caused by the adapter defaulting to the slower 2.4GHz band. Run a network reset if speeds remain slow across all bands after the driver update.