There are some newer driver versions for the Intel® Wireless-N 7260 that were released since 17.0.5.8.
You can get the Lenovo customized version of 17.13.2 from Lenovo Download Center, or you can get the generic version for 17.14.0 from Intel Download Center.
If the issue persists with the new driver, try the following options as they have solved the connectivity issues for other users.
- Review the Quick checks in the document from my previous post.
- Make sure you are using the Recommended Settings for 802.11n Connectivity.
- Check your Windows Power Plan, and confirm that the adapter is set to "Maximum performance", on battery and plugged in.
- For testing purposes, try disabling the Bluetooth radio and check if you get a better WiFi connection.