GTAIV, Brink, BF3, AvP, Metro 2033. All recommend a quad core CPU.
Quad is slowly becoming the new standard for games, but it isn't there just yet. It will probably take another 2-3 years before most games need a quad-core CPU, which brings us to the point: why buy a slower 6-core or 8-core CPU today for games that will only need 6 or more threads in 3 years when we'll have far faster CPU architectures?
The fact is for the foreseeable future, outside of ArmaII/III, there isn't a single game that will be bottlenecked by an overclocked quad-core SB processor. Even now a 2C/4T i3 smokes a Phenom II X4 in games - so not even 4 full-fledged cores can overcome a faster IPC advantage. If you look at
i3, it's competitive in games vs. 1st generation i5-750/760.
I even "downgraded" from an 8 threaded CPU to a 4 threaded one since I wanted higher IPC performance. There isn't any reason to spend $300 on an 8-core BD for the sake of improved gaming performance or "future proofing" for games. There will be plenty of
other reasons to buy a 6- and 8-core BD CPU, but better gaming performance over a 4-core SB isn't going to be one of them.
AMD's current strategy of throwing more cores at consumers didn't work
at all with Phenom X6 vs. i5 and Phenom X4 vs. i3. Sure it captured some consumers, but barely enough to retain 19-20% market share (in fact most of the recent gains came from Fusion). I am pretty sure AMD knows this and did everything possible to make sure that BD has superior IPC and/or much higher clock speeds over Phenom II.