Dear All,
I've been thinking about the temperature fluctuations in a processor, and recalled the
large and rapid changes in processor temperatures that some list members have reported
when the floating point unit is activated.
So my open question is: Do sudden temperature changes cause physical harm to CPUs,
especially those that have only recently been turned on?
Given that integrated circuits do not physically wear out, there are only two failure
modes:
1. Decomposition of gates and other structures by thermal diffusion of doping agents.
2. Thermal stress. i.e. repetitive expansion and contraction due to turning on and off
over time causes cracks to appear leading to failure.
To my understanding, thermal expansion and contraction is the most important failure
mode, and indeed machines that are run continuously are generally more reliable than
those that are turned on and off each day.
So:
1. Those who are lucky enough should run their machines continuously 24 hours. (Hey,
you wanted an excuse to do that anyway?)
2. Are there merits in delaying the running of prime programs by a few minutes after
turning on machines? For instance, a scripted startup could include a plain "sleep
120;" to allow the CPU to warm up slowly before the intense calculations begin.
Yours,
======= Gareth Randall =======
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