Thuban heavily OCed (4+Ghz) draw A LOT of power. Power draw practically skyrockets,just like it does with BD. So no ,power draw is not an excuse. Also I doubt that highly OCed Thuban ,even with OCed NB, could be faster overall chip than PD @ 5Ghz .The IPC deficit is not uniform and varies a lot. In some very important workloads Bulldozer just destroys Thuban. Let me illustrate with some real world application workloads (numbers from techspot's i7-3770K review):

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8150 is 36% faster than 1100T.

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8150 is 28%/20% faster than 1100T.

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8150 is 30% faster than 1100T.

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8150 is 30% faster than 1100T.

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8150 is 31%/8.5% faster than 1100T (MTed pass and low threaded pass)

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8150 is 22% faster than 1100T.

I don't want to link the gaming results since FX8150 is at least on par with 1100T or faster in every game they tested.