Here are some reasons according to our understanding of the Wifi standard of why you may not be able to see 40mhz as easy as before. 1)If an AP is booting up, it will cause all existing AP’s to go back to 20Mhz for at least 30 minutes 2)If an AP detects a Beacon from an AP with 40Mhz Intolerant Bit Set. An AP will set this bit if they have a legacy client. AP will go to 20mhz. a.This basically means if there is a single legacy client connecting to an AP, it will kill all AP’s within its range to go to 20mhz. 3)If a AP receives a message from its client with 40Mhz Intolerant Bit Set. AP will go to 20mhz. 4)If there is legacy or 20mhz only AP in the extension sensitive channel. AP will go to 20mhz. 5)If there is noise on the extension channel. If the noise is above certain threshold, the channel will not be used. AP will go to 20mhz.Download Driver Pack
After your driver has been downloaded, follow these simple steps to install it.
Expand the archive file (if the download file is in zip or rar format).
If the expanded file has an .exe extension, double click it and follow the installation instructions.
Otherwise, open Device Manager by right-clicking the Start menu and selecting Device Manager.
Find the device and model you want to update in the device list.
Double-click on it to open the Properties dialog box.
From the Properties dialog box, select the Driver tab.
Click the Update Driver button, then follow the instructions.
Very important: You must reboot your system to ensure that any driver updates have taken effect.
For more help, visit our Driver Support section for step-by-step videos on how to install drivers for every file type.