You may want to take a look at some of the sleuthing Wendell over on Level1Techs did.
He was able to identify a large group of CPUs used in W680 chipset motherboards (i.e. using stock Intel power curves, never seeing a lick of overclocking/overvolting) which exhibited issues.
It would seem enthusiast ricing is, at best, an aggravating factor to some other underlying cause.