Arris TG 3482 G. What is the wireless output speed (ac 1200 for example)

I'm trying to figure out why we have intermittent problems downstairs in a large house.

We are using the a RRIS model TG 3482G router. What is the speed of this thing?

There's an off a lot of people in this house using a lot of gadgets and I'm thinking it's probably low. If not then I have a different problem then I think I do chuckle

thanks for your help