Well, I was told once that the more you expose a chip to stress-generating heat (for example running a game with a bad quality cooling fan), it drastically reduces its life span, and will also make it slower.

Apparently chips "age", but they still function because or error mitigation, which is witnessed by a performance drop.

To me it's the only explanation why I see so many computers turn slow, despite the fact that I have reinstalled them, cleaned them, etc. I argued many times against the "just put a SSD and add RAM, windows 10 is just slower", but in my mind, I just cannot explain why a newer OS becomes so much slower and memory hungry and unresponsive, even when running very basic programs.

I think there is a myth that chip will always perform exactly the same as long as they work. Chip engineering sounds much more complicated than it seems, and I cannot trust any IT support person telling me to "upgrade".

I'm sure military-grade chips have different designs and cooling requirements, which doesn't turn them into domestic/obsolete products after 3 years.