The best thing to do is to make sure your router isn't sitting on the same port as your cordless phone. There is an app you can download that will look at your connection and show you the best possible port your router should be set on. After that, its all physics. I.E. you're at the mercy of whatever server you are downloading from, number of hops between them and you.
As an aside, AC speeds, like N and G are great for things going on inside the house. File transfers, backing up files to local shares, file sharing between computers, video and music casting etc. Outside the house, its not much help between the modem and the location switching station. There you would need a good DOCSYS 3 spec modem.