Actually, what I said isn't strictly true. AMD has stated that their CPUs don't measure actual temperatures, and a thermal margin of 15 isn't 15 degrees cooler than overheating, but you know it's cooler than a thermal margin of 10.
I like AMD's system, because people tend to flip out for instance when they see a temperature reading if 75c on an Intel chip, and think, "that's really hot", without realizing they can't use their intuition with these things. What's hot for a person is not hot for a CPU, and not all CPUs are the same.