So I bought Edimax wireless adapter and R7000 router. How can you tell whether or not the connection is in ac mode? I use native windows wireless management. Edimax doesn't provide a separate software for it.
One way is look under network properties for the adapter and see what the current link speed is. If it is something higher than 300Mbps, then it is running 11ac 5GHz.
Or you can get something like InSSIDer which will tell you which band you are linking on.