no paper nor any documentation whatsoever accompanied the card
Are we playing 20 questions?
i keep very good notes
what the magic about Barts is that allows it to perform better than Cayman specs-wise, even though it's still based on "old" VLIW5 architecture
Perhaps Barts is better optimized by AMD than Cayman since they had more practice with it. Cayman is newer and the architecture is pretty short-lived.
Hey, ya know, HD 7770 is rather bandwidth-limited, so adding even more core clock only exacerbates the bottlenecking factor of the memory. HD 7770 has over 50% more shader compute AND texturing power than HD 7750 which has the same bandwidth, yet it's only 28% faster overall.
And the memory can't go much higher. Sapphire found the sweet spot with this card - from 1000/1125 to 1200/1250MHz. It is a very narrow sweet spot