Re: There are some substantial improvements.
True but to take advantage of these improvements you are forced to override the stock power limits. Every benchmark I've seen shows very little improvement over the previous 7000 series using the stock power profiles, topping out at 4-7% in production benchmarks. Raising the power limit helps but not dramatically enough to upgrade over the existing 7000 series, at least for me. Power efficiency is important but it feels like AMD is standing still performance wise. However it is very early in the life cycle so maybe additional gains are forthcoming.