This message was posted on behalf of Intel Corporation
Hello, mattmathews. Thank you very much for contacting the Intel Communities Team. I will be more than happy to assist you.
Firstly, allow me to share with you that we do not recommend installing an Intel® Wireless adapter into an Original Equipment Manufacturer (OEM) system due to FCC regulations and hardware compatibility. For more information about this, please check the following link: Regulatory Information Regarding Wireless Hardware Installation or Upgrade
Then, the difference between these two adapters is that the 8265NGW adapter is intended for mobile devices and, the 8265NGWMG adapter is used in desktop systems.