Keep in mind that the 8-core BD is now almost exactly 2x the die size compared to IB (315mm vs. 160mm). That's gotta hurt, because Intel rarely has yield issues AMD has to price theirs BELOW a chip half their size.
I'm surprised they even sell the FX 4000 series, they've got to make next to nothing on it, if anything it should be an OEM only release in limited quantity so they aren't throwing away defective chips.