It's a self limiting situation. There's a set of laws governing successful overclocking.
1. Overclock as far as your computer remains stable.
2. If your lights dim when you turn on your computer, you need another generator.
3. If a capacitor explodes, don't use bare skin to handle it.
4. Use silver before copper.
If you're attempting to overclock your T850 to 1.5ghz, you can probably get the settings correct in the bios, and your computer might even POST. When it locks up on you, that ends the possibility for a sucessful overclock. Don't sweat your temperature if you're overclocking. Your computer will become unstable long before the core melts. If you're not overclocking, then you need to keep track of the temperature.
Unless, of course, you will be keeping that cpu/ram/motherboard for the 10 years it's designed to last. I swap out (completely) at least every 3 years, more like 2.