I work as a software engineer for a chip manufacturer. The fab (silicon manufacturing company) gives only a 5 year guarantee for the smartphone/tablet chips (with presumably some allowance).
As years go by, the chip starts slowly degrading and some of the high performance chips start to get higher temperatures, worse power consumption, needs higher voltages, etc. The power management software counters this by keeping the clocks lower and the voltages higher, causing performance degradation over time to avoid catastrophic failure.
When the same chips are used in products with higher reliability requirements, they are clocked down and more conservative power management software is utilized.
disclaimer: not my area of expertise, I work on something completely different than power management.
As years go by, the chip starts slowly degrading and some of the high performance chips start to get higher temperatures, worse power consumption, needs higher voltages, etc. The power management software counters this by keeping the clocks lower and the voltages higher, causing performance degradation over time to avoid catastrophic failure.
When the same chips are used in products with higher reliability requirements, they are clocked down and more conservative power management software is utilized.
disclaimer: not my area of expertise, I work on something completely different than power management.