Hmm... I always attributed CPU triple faults exclusively to software. If there is any relationship to overheating, that must be a random and probably rare event. Furthermore, triple faults reboot the computer, whereas overheating shuts it down.
With due exceptions (older processors or maybe specific CPU designs), the general last line of defense against overheating is entirely controlled by the BIOS which monitors temperature and shutdowns the computer if it exceeds a certain level. However this is really not desirable, since once you get here you have probably already shortened the life of your CPU and god knows what else.