Re: software based fan speed adjustment

Jack Snodgrass wrote:
When the box boots it really is 'cool-n-quiet'. When I am processing video with mythtv, it gets hotter and louder...

lm sensors reports.... ( my custom report )

(date, time, cpu temps, fan speed, cpu speed )
20061027 03:06:02 +84 +62.6 +77.0 860 1000.000
[snip]
... when there is activity... I get: 20061028 00:07:03 +129 +96.8 +113.0 3835 2400.000
[snip]
... now when the system settles back down, I have:
20061028 08:07:01 +88 +62.6 +95.0 2812 1000.000
[snip]
QUESTION:
... you notice that the CPU Freq goes to 2400 as expected, the fan runs faster... 900rpms -> 4000rpms and the processor gets hotter... all working fine... BUT.... when everything
settles down... the CPU FAN Speed does not....

What do the 3 temperatures correspond to? Notice that the third temp is
still almost 20 degrees hotter than it used to be. I'd bet that it is
the temperature somewhere inside the case (motherboard, PSU maybe) other
than the CPU itself.

So if the "ambient" (for lack of a better term) air inside the case is
now 95 degrees instead of the 77-85 degrees that it was before, it seems
logical that the CPU fan would have to run faster. Whatever it is, that
temperature has not dropped.

It's quite likely that the extra heat from the CPU is trapped inside the
box for a while after the CPU load drops. Better intake and exhaust
fans and better (unobstructed) airflow through the case could help vent
that heat to the outside faster.

But of course, if that's room temperature or anything else, a different
solution will be required.
.

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