Heat can cause long-term degradation of traces within the CPU.  Over time,
electrons can migrate (jump off a trace into "no-man's land" toward a lower
potential trace).  Over time, the migration can in effect blaze a trail
where electrons can flow but shouldn't.  Higher temperature equals higher
resistance in traces and higher electron energy, making migration more
likely.  The 233 doesn't produce as much heat as more modern CPU's, so a
heat sink with fairly good natural convection and ambient air flow may be
sufficient to maintain normal operating temperatures (depending on
environmental conditions).  You will know if you damaged it (unlikely if you
could touch the heat sink without a burn) when it fails or begins locking up
(i.e. wait and see).
Martin Kurr
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> From:         Mark Rode[SMTP:[log in to unmask]]
> Subject:      [PCBUILD] Overheated 233MMX
> The other day I was swapping out a hard drive on my bench box..... Tomcat
> III....233MMX..it is in a open 286 case with a fist rate PC Power and
> cooling CPU heat sink / fan.....normally the heat sink feels cool.
> I inadvertently loosened the connection to the CPU fan and the PC ran for
> around three days.....12 to 16 hours a day...with no CPU fan...just the
> heat sink. I finally noticed it last night ......the heat sink was VERY
> hot.....I could touch the heat sink but it was cooking.
> The amazing thing was I saw no degradation in performance or experienced
> any lockups ....and I have been running NT4 with SETI continuously running
> in the background...so from the moment I boot I have a constant 100
> percent
> CPU use.
> The computer has been performing perfectly. Of course what saved it was a
> 67 to 74 degree ambient air temperature....no cover on the case....and a
> first rate heat sink with thermal grease....
> I started thinking about this and I am curious if the heat necessarily
> damaged or over stressed the CPU even though there have been no failures
> or
> abnormal behavior of any sort ? ?

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