I was shocked to see the fan would never go above 48% even when everything was above 85C, which suggests AMD is more concerned about acoustics. After I put the thermal paste the fan would run 10% lower which made for a better experience. Here you can see my Vega 56 running 33C while using Fixfox with 20+ tabs open. Again, I'm not experiencing the black screen issue but maybe that's because my temp doesn't get that high.Think your right. AMD seems to be much more worried about spinning fans up when needed the last couple generations. And ya no way 100c+ is good for anything. Highest I have noticed mine get was 95/6 or so... but at that point the fans where at 2800 rpm which is more then a bit loud. Since then though I have tuned my rear out take fan and I swapped the 2 120mm top fans I had with a couple 140s I had around. Have noticed the junction sits more around mid-high 80s now which makes me feel a lot better. Made things a bit quieter as well... the difference between 2200 rpm and 2800 rpm on those GPU fans is pretty huge.
I'm not on my gaming machine right now... but if I'm browsing on it, or doing pretty much anything non game related the fans shut off... so I think it sits around 45 degrees or something. I'm sure I could get it down by disabling fan shutoff and spinning the fans at 1000 rpm or something, but its nice when I'm not gaming that the system is very quite. No hiding when I stop doing things I should be doing to fire up a game though. I played a round of dota the other day... and I don't think my 5700 fans spun over 1000 rpm the entire match.
There was a time when motherboard manfacturers like MSI and Asus wouldn't have sufficient VRM's or VRM cooling for AMD FX motherboards and like any mosfet it shuts off to prevent damage and of course the system crashes. This maybe the issue people are expriecing and not a driver issue? Doesn't make AMD sound any better honestly.