but from past experience and what we currently know...
x570 has much beefier VRMs than x470 and b450. so by extension/speculations/assumptions/magic (or whatever you want to call it) on balance of probabilities...an x570 board's VRMs would be much better suited to running a 3900x/3950x
that's not to say that the x470/b450's aren't up to scratch...it's just that x570's are better.
Well a Low tier X570 might not be just that....
Ive tested loads of mobos...and sweeping statements like this grind my gears....
don't get your knickers in a twist.
as i said...we can only go by what's currently available out in the open currently - and with lack of concrete evidence, it's no doubt that one may draw different conclusions from this as a result.
that being said, this is what we know at the moment:
X570 Phases
look at the low-end x570 gaming x - 5 pseudo-doubled phases with 60A powerstages = 600A (granted it's of lower quality)
mid-range aorus pro - 6 true doubled phases with 40A powerstages = 480A
top end aorus ultra - 12 true phases with 50A power stages = 600A
not even going to compare the aorus master as that's a halo product
now unless you've got a top end x470 board (eg taichi/c7h), it's not going to be even close to the bottom tier x570 boards...
taichi = 2(6)*40 = 480A
c7h = 2(5)*60 = 600A
x470 strix-f = 6*60 = 360A