Intel recommends that you always use the latest drivers provided by your computer manufacturer: Computer Manufacturer Support Even though our drivers on our Intel® Download Center may be newer, there is a probability that they may not be compatible with your system considering the modifications the OEM does on the wireless adapter in order to meet their system requirements.
1 - Firewall and antivirus configurations may also impact directly on the connectivity, please check the seetings in order to discard any possible interference.
2 - Disable the Power Saving Functions: Go to Control Panel >> Power Options >> Set the High Performance and apply to default settings.
3 - Considering you already set the Transmit Power to 5. Highest we advise that you check the Change Plan Settings >> Change the Advanced Power Settings >> Wireless Adapter Settings >> Paower Saving Mode and make sure both on Battery and Plugged in are set to Maximum Performance.
4 - Change the wireless channel - Changing your wireless channel might help increase range and performance specially if you have neigboring networks set on the same channel or interferences from other electronics. There are third-party products that can check channel usage such as the Vistumbler or inSSDer - *Note: These links are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.
5 - Regarding Channel Width, The higher speeds of wireless N and AC can only be achieved by using the 40MHz wide channels. For wireless N (and possibly wireless AC), the default channel-width set on routers is only 20MHz. But you can login to the control panel of the router and in the wireless settings change the channel-width to auto 20/40MHz.
6 - Please also verify if your router is running the latest firmware as it may contain fixes that might help improve your experience.
Alternatively, you can also check the solutions below: