AMD Ontario APU pictured,die size ~77mm^2

[informal]

You made to many assumption here. Based on what we know about bobcat architecture, it should be in range of athlon64 perf.
Lets see.
Bobcat:
2 decoders, 2 ALU+2 AGU (max 4 uops per cycle), 64-bit fpu (max up to 2 uops ).
Athlon64:
3 decoders, 3 ALU/AGU (max up to 6 uops per cycle) 64-bit fpu (max up to 3 uops per cycle).

If only the number of decoders would tell the whole performance story, it would be easy.You can say that Bulldozer is almost equal to Bobcat then and on the A64 level of performance.Which is of course ridiculous.