It's an FX cpu. The only place you should be reading temps is from Overdrive, using Thermal Margins. If what you are seeing is a Thermal Margin of 15°, then you are running hot, but 15° away from any major issues.
HWInfo doesn't work. None of those monitors do. It's FX, not Intel. The only other program that does, apart from Overdrive is Coretemp, and it too must be set for Thermal Margins.
Max core temp for All of the FX cpus is 63°C, but since the FX do not have on-core thermal sensors the way Intel does, that 63°C was taken from a prototype cpu that had on core sensors added, which were not included in production models, so physical readings are impossible. Thermal Margins use complex algorithms that use cpu voltages, socket temps, vid etc to come up with a figure, but that figure is just a representation of how much room is left. It's not an exact number.
So when OD says a TM of 58, you have all kinds of room, that's one chilly cpu, but it's not running at 5°C (63-58), it's actually running at @ 10-12°C above the room ambient temp. (that's @ 6°C or so below case ambient temps.
You could change your current 0.8v vcore to 0.9v and see that TM go from 58 to 48, but that's not a 10°C difference, just a representation of what room you have left.
40+: is it even running? Pc asleep?
30-40: still got all kinds of room.
20-30: hey! It's alive and kicking.
10-20: ooh it's warm in here! Pay attention!
5-10: what ya doin? I'm cooking! Need help!
0-5: call the fire department.....
-1+: you in for it now, hah, shutdown city.
The exact number doesn't matter. It's what that number is that does, where it is.