According to your post, we understand that the original wireless adapter has been replaced for the Intel® Dual Band Wireless-AC 7260. If that is so, it may be that this adapter is not fully compatible with your system, and with that being said, we would like to inform you that Intel does not support integration which is when the original wireless adapter is replaced. Please access these links for further information on this matter:Intel® Wi-Fi Products — Regulatory Information Regarding Hardware Installation or Upgrade and Intel® Wi-Fi Products — Why Doesn't My Laptop Recognize My New Intel® Wireless Adapter? We recommend first that you contact your computer manufacturer. Here you can find your computer manufacturer information: Computer Manufacturer Support
On our best effort to assist you on this matter here are some steps that might help you resolve this issue:
- Make sure it is running the latest firmware.
- Change to a less crowded channel. Most routers come by default set to channel 11 and 6 which, depending on your sorroundings, it may be really crowded and impacting your connection.
- Change the encryption to WPA2-AES as this type of encryptions is known to provide better performance: Wireless Networking — Data Rate Will Not Exceed 54 Mbps When WEP or TKIP Encryption is Configured
- Other factors such as MIMO, interferences from other devices can also impact the connection.
- Disable Power Savig Function: Go to Control Panel >> Hardware and Sound >> Power Options and set it to High Performance
- Check and if necessary change the Power Plan >> Change Advanced Power Settings >> Wireless Adapter Settings and make sure both both On Battery and Plugged in are set to Maximum Performance.
- Also, go to Device Manager >> Network Adapters >> right click on the Intel® Dual Band Wireless-AC 7260 and access Properties and from there, select Advanced Tab and once you there, select the value of U-APSD Support and Disable it.
- Check the value of Transmit Power and make sure it set to 5. Highest.
- Set the Preferred Band to Prefer 2.4GHz band.
- Set the HT Mode to HT.
- Set tje Channel Width for 2.4GHz to limited 20MHz
- Set the value of Roam aggressiveness to Lowest.
- Set the Ad Hoc QoS mode to WMM Dasabled