CPU temperature Thinkpad R61

[Fernando Cassia]

2009/10/16 Christoph Höger <choeger at cs.tu-berlin.de>:
> Am Donnerstag, den 15.10.2009, 17:34 -0500 schrieb Mikkel:
>> Christoph Höger wrote:
>> > Hi,
>> >
>> > I just wondered why my fan always runs after a while. After closing
>> > firefox (which took 50% cpu along with X) I now have a load of roughly
>> > 0.06 - barely nothing computed at all. Both cores are in the lowest
>> > config and yet my cpu temperature goes from 42°C to 47°C in roughly 2
>> > minutes (and back by fan activity).
>> >
>> > I would understand this if there was some load, but what causes my CPU
>> > to heat if it does nothing? Design failure? Has anybody seen such a
>> > thing?
>> >
>> > regards
>> >
>> > Christoph
>> >
>> When was the last time you cleaned the dust out? Also are the air
>> vents on the laptop clear when in use?
>
> I am aware of that dust thing (I am going to give a compressor a try),
> but the heat goes up when the notebook and the fan is idle. That should
> not have anything to do with dust, right?

When computers are idle (but active, I mean NOT hibernating or
suspended) it doesn´t mean the CPU fan stops completely. Sometimes
those spin at very low rpm so you don´t "hear" it, but the fan IS
spinning, albeit at very slow speed.

If there´s dust inside the heatsink system, the fan spins slowly, but
air doesn´t move inside, because of the dust. Hence temperature builds
up until it reaches a certain threshold, which is when the system-bios
increase fan speed to lower the temperature.

Here´s what a totally clogged up notebook fan-heatsink looks like.

http://img147.imageshack.us/img147/808/heatsinkuy8.jpg

Obviously this is an extreme case. But that´s what it gets to
eventually if you never blow compressed air to clean the very thin
ducts inside.
FC