i think its not that easy, cause when you look at the gainestown score and then at the bloomfield score you see where the difference lies. Gainestown has 8 threads on 8 physical cores, while bloomfield has 8 threads on 4 physical cores and 4 virtual cores.

And if you compare gainestown 8 threads (aka HT disabled) with your opteron 8 threads scores, the result of gainestown are quite impressive.