That is not true. Gnexus did some really detailed comparisons of the two, they had the exact same efficiency. A 10900k locked at 125w performed similarly to the 5800x in most multithreaded workloads, while it was much faster when power unlimited drawing twice the wattage. I know you don't like Intel but please, come on, let's not skew the facts. Also, the 10850k was released around the same time that cost as much as the 5600x, while handily beating it. Very handily I might add.
And neither the 5800x or the 5600x was 30% faster in games, now you are just making stuff up...I mean come on.