The 62 degrees reference is for the processor's maximum case temperature, and is usually referred to as "Tcase max". It basically represents the maximum allowable temp of the metal heat spreader, which contacts the heat sink.
The core temp is not the same as the Tcase temp, and will usually be higher. Phenoms have a thermal trip which will begin throttling the clock speed after it exceeds the Tcase max temp by a certain margin. If it goes much higher than that, it will reset and force a reboot, or BSOD.
It's a bit more complicated than that, but that's a pretty good explanation in non-engineering terms.