On 27 Feb 2001, at 8:56, Brian Last-Name wrote:
> I am running a Cyrix 233 OC'ed to ~266 by a
> faster bus speed. I cannot touch the processor heat sink for more than two
> or three seconds without pain, and the voltage regulators are even hotter.
> It has been running trial testing for over two years without many "issues".
Older designs are more resistant to overheating because there is a
lower probability of electrons released by excess temperature from
making their way through to an adjoining circuit. The circuits are in
much closer proximity with modern high-density designs.
People's tolerance to heat pain does vary; because of thermal
conductivity, handling hot metal isn't easy, most people will begin
to register pain at ~50C (120F). At ~70C (156F) few people will be
able to hold hot metal for more than a second. A few degrees above
that and touching for more than a split second will cause obvious
burns.
Casting my mind back a few years, I seem to remember that Cyrix
processors were noted for hot running.
Voltage regs running hot are fine. They're not subject to data
corruption caused by overheating. Either they work, or they cook
themselves to death.
> I havent even been using frag tape or heat conducting grease.
These are more neccessary with newer designs, because their heat
ouput per unit area is much greater than with old designs, and it's
therefore more neccessary to conduct excess heat away from the chip
efficiently.
> What is the maximum operating temperature (recommended) for a processor?
> I will measure the temp. at the bottom of the heat sink while operating.
Technically you're looking at around 130C at the hottest point inside
the circuitry of the working chip. There's _no way_ to measure that,
without more access to the chip than a working processor usually has
available, and even then without specialist equipment like a
pyrometer.
The position of the temp sensor depends on the processor cartridge
and/or motherboard design. Slotted Intel PII/PIII have the thermistor
mounted on the small board inside the cartridge; slotted Athlons
don't come with a thermistor, if you want that option you have to
mount one yourself, the only place to do it is to wedge the
thermistor between the fins of the heatsink. Socketed designs usually
have the thermistor mounted in the "hole" in the CPU socket,
immediately under the processor itself. Obviously these different
mounting methods will all read "low" compared with the critical
temperature internal to the chip, but how low depends on many
factors. Therefore it isn't possible to give a maximum temperature
without knowing several other variables.
If your system has been running for two years, still passes the
Prime95/mprime self test & isn't either crashing frequently or
producing error messages frequently when Prime95/mprime is running,
it's not actually overheating. Don't worry about it. Start worrying
if and only if you start seeing symptoms which could possibly be
attributed to overheating.
My standard procedure is, some time around July when the weather is
warm, to remove all the "SelfTest" lines from local.ini.
Prime95/mprime will then re-run the self-test next time it needs to
use each FFT run length. If overheating is going to hit you, it's
_much_ more likely to be a problem when the system is operated in an
unusually warm environment.
Regards
Brian Beesley
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