Why is all of this centered around single threaded benchmarks when almost nothing is single threaded anymore?
Because when a 4-core processor goes against another 4-core processor (price point) then it comes down to performance per thread as to which is better?
Multi-threaded benches are cool but it wouldn't be a direct comparison if you put the 8-core BD against a 4-core SB (non-HT) SB, price or performance wise.
If you strip the comparison down to price/performance, then you are pitting 4v4 and 8v8 (theoretical), so knowing who performs better PER CORE becomes relevant. At that point it all really boils down to IPC and clock rate.
With multi-threaded stuff it might also boil down to whether the threads break down and run evenly on both platforms, but that's really more application dependant than hardware dependant unless the hardware design is really borked.