Here's an update... http://www.tomshardware.com/column/01q4/011029/index.html.
In a nutshell, motherboards that properly support the Athlon Palomino core processors with the internal thermal diode should protect the processor from burning-up by shutting-down the system. That won’t protect data that hasn’t been saved. Boards that implement this feature are not yet available. I.e., all boards currently claiming Athlon XP compatibility may be compatible, but they do not fully support the processor. Most, if not all, of these boards have a thermister in the center of the socket A That should protect the processor in all cases where the fan fails, probably will not protect them in the extreme case where the heat sink is removed form the processor.
In the mean time, I've had many heatsinks come entirely loose from the socket when shipping a new computer via UPS. What happens if the customer doesn't hear it bouncing around in the case and turns-on the computer? Smoke!
I will have to call the customer and have them remove a side of the case and verify that the heatsink is OK. Not a good situation. Intel's solution appears to be superior. Larry