A bit of a trip down memory lane for me. I performed an analysis of the thermo-mechanical cyclic fatigue in later packages using detailed CAD, FEA and empirical tests. A lot of work went into finding it wasn’t a big deal for the most part. Still, I don’t recommend that museums power cycle old PCs daily…
Knowing nothing about how survival/durability testing is done in VLSI: how did you do the empirical tests?
For example, I know that thermal samples for the Pentium 5-era Xeon (Jayhawk) were produced, but I'd always wondered Intel went from the dummy to realizing "oh, shit, this is going to be way too hot in the long run."
I can’t really speak to the thermals other than as an input to my work. I was narrowly focused on the cyclic loading based on the temperature gradients (etc.) I was given.
For museums, would it be an option to instead of a cooler have a temperature control unit that keeps the package at a set temperature no matter wether the PC is operating or not? Just heating the chips surfaces might be cheaper than having the full PC on 24/7 with a semi constant load.
The PC would still heat up when started. You would need very precise temperature control to avoid that. That could be quite difficult to do
With a couple of kelvins of tolerance a PID controller could handle this fine