On Monday 22 July 2002 16:55, you wrote:
>
> Thank you and everyone else, both on- and off-list, for your helpful
> suggestions. I took the cover off and had a look. The HSF looked like the
> inside of an old vacuum cleaner, so I used a new one on it. :-) The fan
> speed is now back up to 4600, and the processor temperature has dropped by
> 10 degrees.
>
> While this is probably what tipped the system into instability, I'm not
> convinced it is the sole cause of the problem, if, as you say, 50 degrees
> is not excessive.
This does depend on whether the sensor is correctly installed in the mobo -
socketed AMD Athlon/Duron processors have the sensor located in the "well" in
the middle of the socket, rather than in the processor package. It should
sort of stick up a bit so that the springiness of the mounting wires holds it
in contact with the installed processor package base. If it is pushed down to
the bottom of the well, out of contact with the processor package, it will
underread badly - even if the reporting software maps the
current/voltage/resistance measured by the sensor to temperature correctly.
The temperatures & voltages reported in the BIOS Setup "health status"
display should be correctly mapped but are, of course, impossibly
inconvenient to use on a running system!
A small amount of dust buildup on the leading edges of fan blades is
inevitable. The problems with buildup of excessive dust/fluff are (a) it gets
stuck between the heatsink fins, reducing the effective area of the heatsink
and restricting airflow - possibly to the point where fan rpm reduces, though
this usually involves fan blade stalling with a marked increase in
aerodynamic noise; (b) lumps of compacted fluff can be thrown from the fan
blade, whereupon they stick to the inside of the duct and are clouted by each
passing fan blade; this makes a terrible noise, and failure of the bearing
due to repeated shock loading often follows shortly thereafter.
I prefer to mount cooling fans onto heatsinks so that they suck hot air from
the heatsink rather than blow cool air onto it. This does result in a small
decrease in efficiency of the HSF combination when clean, but helps prevent
the heatsink from getting clogged with debris. The "reversed airflow" trick
is particularly effective when combined with an adapter allowing a 80 mm fan
to be fitted to a heatsink designed for a 60mm fan; the advantage here is
that the larger fan can be much quieter, due to being able to shift air at
the same rate whilst rotating at a much lower speed.
> > to test your processor, i recommend www.memtest86.com
> > it is a memtest in first place, of course, but it also tests the
> > processor
> >
> > You can test your system with madonions 3DMark 2001 SE. This program
> > will heat up your ram, cpu and grafik card.
If you are running Windows, you could also check out Sisoft Sandra. The
"free" limited edition will do enough.
http://www.sisoftware.co.uk/sandra
One final point - I heard of a system built by a well-known overclocking
expert who had a problem with the system "blue screening" at intervals for no
apparent reason. (Sounds typical of Windows systems to me; however...)
The problem persisted even when everything was returned to rated speed.
Eventually it was traced to the chipset fan; occasionally this would seize
(probably due to blade fluff shedding) for a few minutes, but then restart
itself, so that a quick check of the operation of the fan showed no obvious
fault. Operating the system with the cover off, it was noticed next time that
the system crashed, the chipset fan was not running.
If you _do_ have to deal with a suspect/failed chipset fan, it is now
possible to obtain large area passive heatsinks which can be used to replace
the chipset HSF; these are ovbiously going to be more reliable & less noisy
than a replacement fan, though they may not be suitable for (or indeed
compatible with) all motherboards.
Regards
Brian Beesley
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