[plug] Hot and bothered CPU hankers for cool breeze

[Bernd Felsche]

[Decided to change the subject line... test your spam-traps :-) ]

On Tue, Dec 16, 2003 at 04:12:26PM +0800, Chris Caston wrote:
> On Tue, 2003-12-16 at 14:28, Bernd Felsche wrote:
> > I've only once had a problem with an AMD "failing"; that was a Duron
> > where the fan (third party) stopped and the processor "cooked".
> > After serious testing using a new heatsink and fan (as well as fresh
> > goop), the Duron showed no signs of permanent damage.
> > 
> > I've had an EPIA-M with 933MHz CPU stall on me because the CPU fan
> > blades had been stopped by some cables... it slowed to a crawl
> > first. No problem at all once effective cooling was restored.\

> Generally a CPU will run at 55-80 degrees but will give serious errors
> 85-90 degrees is where it starts to fry.

AMD seem to cope with 80C quite well.

> The cooler the better: add 60 or 80cm casefans and PCI slot fans

Crikey... what sort of case do you have to be able to mount 80cm
fans? Those things are like in SciFi movies where the hero has to
get between the slowly-rotating blades to save the planet. :-)

OTOH, you might have meant 80mm ... And they are not all alike.
If you get one that blows a howling gale (50cfm; 1.4m^3/min) at full
voltage (12V), then you can lift its "ground" to the 5V rail in
winter for a civilised noise level. An SPDT switch on the back of
the machine is all it takes.

Low-noise fans tend to have much-reduced flow rates for their size.
There are some new cases coming onto the market with low-speed 120mm
fans and large vents. Definitely worth a look. Unfortunately, some
take only low-profile 120mm fans that are 25mm thick. The "proper"
120mm fans are 38mm thick and can shift about 3 cubic metres of air
every minute; at a 46dBA noise level to match (e.g. Sunon KD1212PMB1-6A).
Of course, the flow rating _isn't_ through the usually-restrictive
vents (if any) on a PC case.

But then, an IBM x-series server has noise levels around 56dBA at
one metre when its fans kick into high speed. Certainly works well
to mask the complaint that might otherwise be heard from lusers. :-)

> These measures can drop CPU temp dramatically. Sometimes just
> adding a few fans can give you a drop in 15-20 degrees other times
> the difference seems minimal.

The important thing is to get a flow _through_ the machine, not a
circulation or short-circuit between unmatched fans. It doesn't hurt
to give the hard drives a first-bit at the cool air either.

> An incorrectly placed CPU fan/heat sink will also cause excessive heat.

BTDT. :-(

-- 
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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