Had a 2500K running at 4.5Ghz for nearly 10 years and it's still works like new. My mate is still using that machine, I donated it to him when I moved upI've only ever cooked one CPU, was back in the 90s when you could hand solder a motherboard...... meaning there wasn't much space for safety mechanisms
Interesting side note. I've never ever known a CPU to actually just die. I've got a drawer full of CPUs and every single one of them work. I overclocked my old 2700k to the edge, ran it 24/7 for about 8 years and it never put a foot wrong.
They are so much harder to kill than people realise