Whenever a new wireless standard gets approved you expect faster speeds and longer range.

From everything that I've read about it, it seems that AC will only transfer over the 5GHz band and up to 3Gbps. Studying the new AC routers on the market, it seems that they will transfer over 5GHz and 2.4GHz. And 5GHz will only transfer at 1.3Gbps. Which isn't what AC is supposed to be. I know there is a difference between what the standard actually says, and what products will actually do, but is there any reason for this? Is there any other main differences between AC and N? I've heard people discussing AC and saying that it's finally "fixing" what N was supposed to fix... what do they mean by that? Any security benefits?

I have seen this image online:

Will AC really do that? Will that require an AC network card in my laptop for that to actually happen? Lastly, will the router only be able to communicate with AC devices if I have beamforming technology on?

I know it's a ton of questions, but most articles online seem to be outdated, and don't provide too much reliability.