OK..I am going to say uncle and once again missed the better stepping

it now looks as more reports are here and elsewhere the
170 0550 VPMW is better for having a chance at 2.9-3.0ghz at a low vcore even on air

looks like 50XX substrate are best???

Of course I was able to get my hands on a 170 0550 upmw 434L substrate..I hope it deos better than my 0546 xpmw or at least as well on lower vcore....