Pretty much what u said in the first part... Winbond aint testin' 'em but you bet your ass that Mushkin is before they sell 'em or else they wouldn't be able to put the speed guarantee on it.
I haven't been able to hit 3ghz with this proccy yet... 2977 max as of now. Anything over approx. 2915 and I get the random irql_not_less_or_equal BSOD's.