[iker0]

Asking about bottlenecks with current CPU's is pointless, as all the current cpus have enough power for anygame engine, the only time a cpu could possibly create a bottleneck is if it wasnt upto the requirments of the game but the gfx card was, as the cpu would be able to keep up at that point.
this is all IMO

 

[iker0]

that is a good look at it with the deminishing returns, but has no real relevence to my post as i said there is no game engine that will really need any more cpu power then the 3.6 will give thus not really creating a bottleneck in current games, you are quite right though.