It is too bad the marketing guys have been getting away with telling lies about wireless. There really is no rate that will give you 600mbps. They are likely adding the 2.4g and 5g rates of 300mbps each to get that. A end machine can not use both radios at the same time so it can never combine them.
In addition even the 300mbps is a lie. That is some theoretical lab rate it ignore real life facts like data must go both directions between the router and the end devices.
If you look at some of the more reputable testing sites you will find that a average rate of about 250mbits is the best you are going to get. Even that is using nic cards that have 4 antenna which are rather rare. Unless you are sitting right on top of the...