Unless they disable Turbo Boost (which is horrible for performance, but great if you want benchmark consistency), the CPU will automatically overclock until it reaches the limits, adjusting both voltage and frequency.
All the evidence I've seen points to electromigration as a cause of this degradation, and IMHO excessively aggressive automatic overvolting by Intel's microcode is to blame.
There is actually a simple experiment which can determine whether that is true --- remove the fan from the heatsink, or even let the CPU run without a heatsink. As the CPU will automatically throttle once it reaches its designed maximum temperature (and AFAIK that is a hardcoded limit), it will lower its frequency and voltage to maintain that temperature. If this results in a stable CPU, while the one that has great cooling becomes more unstable, it confirms the hypothesis.
There are numerous stories of machines where the heatsink was not in contact with the CPU for some reason, yet they remained perfectly stable (but slow) for many years. I can also say that I've had an 8th-gen i7 running at 100% 24x7 with all power and turbo limits disabled, with its temperature constantly at the design limit of 100C, and it has also remained stable for over 5 years.
> There are numerous stories of machines where the heatsink was not in contact with the CPU for some reason, yet they remained perfectly stable (but slow) for many years.
I once had a laptop, which came from the factory with the four screws which hold the heatsink to the CPU missing. It was very slow, and shut down after a few minutes (the reason being thermal shutdown in the BIOS event log helped diagnose the issue). After the four screws were replaced (each screw came in its own large individual cardboard box), it worked fine for many years, BUT after a couple of years (still under warranty), the motherboard failed with a short in the power input. I suspect that all the extra heat from when the CPU was without a working heatsink went to the power supply components through the motherboard ground plane, and cooked them, significantly shortening their useful life.
>Unless they disable Turbo Boost (which is horrible for performance, but great if you want benchmark consistency), the CPU will automatically overclock until it reaches the limits, adjusting both voltage and frequency.
Turbo Boost (and Thermal Velocity Boost if applicable) frequencies are according to specifications, it's not an overclock.
That's a lot of cpu time. Maybe they just don't make them like they
used to. If there's some crazy complicated numerical or combinatorial
problem you've been trying to crack, do tell.
All the evidence I've seen points to electromigration as a cause of this degradation, and IMHO excessively aggressive automatic overvolting by Intel's microcode is to blame.
There is actually a simple experiment which can determine whether that is true --- remove the fan from the heatsink, or even let the CPU run without a heatsink. As the CPU will automatically throttle once it reaches its designed maximum temperature (and AFAIK that is a hardcoded limit), it will lower its frequency and voltage to maintain that temperature. If this results in a stable CPU, while the one that has great cooling becomes more unstable, it confirms the hypothesis.
There are numerous stories of machines where the heatsink was not in contact with the CPU for some reason, yet they remained perfectly stable (but slow) for many years. I can also say that I've had an 8th-gen i7 running at 100% 24x7 with all power and turbo limits disabled, with its temperature constantly at the design limit of 100C, and it has also remained stable for over 5 years.