What if Windows crashes? It's better to attach a thermal sensor to the heatsink, I think.
Well, what if?
We don't live in the AMD Athlon era[0] anymore. Modern CPUs are designed to boost until they hit a thermal limit, improper cooling is just going to result in a lower clock speed.
Just send a heartbeat every few milliseconds and set fan speed to 100% if it died. Bonus: You get an audible indicator that the system crashed.