[mythtv-users] Slightly OT - Controlling the CPU fan

[Jim Reith]

>  > Even though my Myth backend does not sit in the lounge, it does sit in
>>  the study and the fan noise is driving the family nuts to point they
>>  want the backend shutdown when they are in there.
>>
>>  I have done heaps of searching around and can't seem to find any solid
>>  info but I would like to be able to throttle back the fan on the CPU
>>  when the backend is idling as it seems to most of the time.
>>
>>  I have lm_sensors running and I know the speed of the fan, but I can't
>>  find any way to control it.  It is a Sempron 2400 sitting on a crappy
>>  generic mobo.  Also, I am sure I could afford to turn the fan down as
>>  the highest temperature the CPU has gotten to so far is 50 degree
>>  celcius (although it is winter-ish here in QLD, Australia atm).
>>
>>  Anyways, does anyone have any suggestions other than sticking the box
>>  in the garage?
>
>You could buy a Zalman fan - they're very quiet. I have one and I've
>been very pleased with it.

Chances are the fan speed is controlled by the motherboard and the
only way you can really control it is by reducing the temp in the
case.

Since you said you were using lm_sensors I assume you've seen this page?

http://knoppmythwiki.org/index.php?page=Power+Management

I found that making my (3) disk drives sleep after being idle for 5
minutes dropped my case temperature 10 degrees

mbmon -c 1 -t > starting_temp.log


# more starting_temp.log

Temp.= 55.0, 25.0, 44.0; Rot.= 4787,    0,    0
Vcore = 1.65, 1.65; Volt. = 3.34, 4.92, 11.80, -10.74, -4.66
Thu Aug 11 18:34:20 EDT 2005


# more spundown_temp.log

Temp.= 45.0, 25.0, 32.0; Rot.= 4591,    0,    0
Vcore = 1.66, 1.65; Volt. = 3.34, 4.92, 11.80, -10.74, -4.63
Fri Aug 12 05:43:42 EDT 2005


<once the weather cooled off>

root at mythtvbox:~# mbmon -c 1 -t
Temp.= 43.0, 25.0, 32.0; Rot.= 4530,    0,    0
Vcore = 1.65, 1.66; Volt. = 3.33, 4.92, 11.73, -10.74, -4.63
Mon Aug 15 06:26:53 EDT 2005

One of the other suggestions I've seen but not tried is to use 12v
fans but run them off the 5v supply so they spin slow and quiet.
There are also adapters so you can dial down the fan voltages with a
little pot. I agree that the Zalman fans are VERY quiet. I have one
also. I've also bought round IDE cables to help case airflow and it
happens that there are some on sale VERY cheap this week
http://store.yahoo.com/svcompucycle/clearance.html (at the bottom of
the page)

One thing you want to make sure of is to not turn the fans down
manually and fry your CPU
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