Netgear N300 C3000 Wifi issues

Much more info is needed because you first need to determine if its an issue with your incoming speed (probably not) or your wifi. Wifi is harder to diagnose. 

So lets start with the modem side. 

1. What speeds do you pay for?

2. you put you're getting 80mb/s over wired. That's great if thats what you're paying for. 

3. If that's not what you're paying for, can you take a screen snip of your modem connections page and log?

Wireless.

many things impact wireless speeds. This include home materials, device you're testing with, interference, etc.

1. what is your housing materials?

2. What device are you testing with? Have you tried a different device?

3. You put using your xbox upstairs. Is the C3000 in a basement having to go through a main level and then to the upstairs or is it on the main level?

4. Have you tried changing wifi channels?

5. If you do a wireless channel scan, how many networks show up in your area?

The issue with wireless interference is that 2.4ghz broadcasts further and has less channels available than 5ghz. So it tends to have more interference. If you're in an area with a lot of wireless (like an apartment/condo), you'll have issues even when you optimize the signal. 5ghz doesn't broadcast as far or through as much but has a much higher throughput (speed). Any thoughts of adding in a access point that you just plug into the c3000 to give you 5ghz signal?  As well as the C3000 is still a wireless N device. Getting a little older to be running streaming services if its in an environment that struggles.