Well, all chips are designed with the standard room temperature in mind, which is 21C. I can't say if that would be the best temperature to run at though.....
Very few people would bother with keeping a chip around as long as possible. The only people who would continue to use really really outdated would be in places where actually physically changing the system would be really hard... space for example (I believe recently NASA was buying a whole rocketload of 386 chips or something....)
For most other people, I'd say keep it below 50C operating temps, and you''d be upgrading the computer before the chip reaches half its lifespan
![hellokitty[hk]](/community/data/avatars/m/169/169488.jpg?1355088591){kind=avatar}
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