The newly bought Inspiron 3650 desktop has slow Internet connection. I have an old Dell laptop Lattitude E5430 placed next to it. I would expect them to have same speed. Running the speed test on both computers (through the cable provider's (Optimum) website), however, the desktop is giving me very slow results around 11M while the laptop is showing what I have purchased for (50M).

I tried to resolve the issue. I have updated the driver of the network card and firmware. I have also seen ppl suggesting to enable the mode n. However I do not have this option (see attached screenshot).

My router has both 2.4 and 5 Ghz. It seems that the laptop is connected through 5 GHz while the desktop is 2.4 GHz. Not sure if this is the reason however I cannot change the bandwidth through settings.

I have attached the screenshots that I think can be useful. Can someone help me figure out what is going on? A million thanks!