Slow WiFi Inspiron 17 7000 Series

Hi,

I have an Inspiron 17 7000 Series with the Intel(R) Dual Band Wireless-AC 3165.  I am using a Motorola MT7711 Modem/Router.  I am getting ridiculously slow download speeds through wifi (40-50 Mbps). I have had my cable provider out multiple times and they are not the problem. My wired downloads are fine. 

Need Dell input on how to correct this issue.

Thanks,

Dar