no so much each system is different...more like how you run your ram decides how your vtt voltage runs at...
i have seen this on at least 5 boards....
and pctools can bench with no vtt running vantage.
where i can bench with anywhere from no vtt to +325 depending on how i run my ram or what type of ram im running..
q56 and mrnatural can as well... meaning they can run it very low.
(speculation of course)
i use to run it at +425, then found that that was all wrong..lol
same with cpu voltage.....