Hi, guys. Just found this thread while looking for something else, and since I have the same computer i thought about write you a couple of lines.
Right, so a while back I read too the info the OP points to. And a couple of years ago I used to have the fan almost always active. This isn't the case anymore, and many things contribute to this. Possibly you don't have a problem anymore, but perhaps you find something of the following interesting. Right. Our laptop is not one of those modern machines with a good cooling design. The heat sink is pretty small, and the fan not very powerful. On top of that (at least in my case), the dedicated ATI card, while reasonably good, dissipates a lot of heat. I have no idea about how to control de fan speeds; I read something about it, but I'm not really interested. The approach that worked here was to optimise the power savings of the machine as a whole.
I'll list what I think had the highest influence in the behavior of my laptop in this respect, from highest to lowest:
1. Build a kernel with HPET enabled.
2. Find and take rid of bad software for power saving.
3. Lower the GPU clock when not using it for intensive 3D.
1. You probably know that our board (ICH4/ICH4-M) supports HPET
http://en.wikipedia.org/wiki/High_Preci ... ent_Timer/ , but is not activated by default (actually, the developers just found out that it had that feature). To activate it without compiling and using a patch you need a recent kernel (something like 2.6.23 I think) and the boot parameter 'hpet=force'. If Powertop doesn't suggest anything regarding this it means that it's activated.
2. After that I checked what was causing the proccessor to work. Everything you can find in
www.lesswatts.org can possibly apply. To summarize: make sure your CPU reaches the C3 sleep state. To do this you can't have any low speed USB device attached to the computer, so no mouse, no external HD and no anything for normal use or it'll heat up quite quick. Have an eye on those applications that constantly wake up the CPU. From my experience, you get a quiet environment if you achieve less than 30 wakeups/s (and of course most of the time in C3) when idle.
3. My gx card is an ATI mobility 9700, I don't know about yours. As I said, it really gets hot when gaming; and even idling, it contributes a good deal to the temperature on the right side of the laptop, exactly where the CPU is. Two different solutions for the two different drivers you may be using (given that you have the same graphics card):
a) OSS driver. Apart from the 'dynamic clocks' option in xorg.conf, I use the rovclock utility to lower the GPU memory and core speed when I use the computer for normal tasks (note that I don't use compiz nor anything like that, so for me 'normal tasks' don't require any 3D out of the gx card). I found that setting the core and the memory to 65 doesn't give me any screen corruption and keeps the unit reasonably cool.
b) Fglrx ATI driver. Make sure you use aticonfig --set-powerstate=1 when not requiring heavy use of the graphics unit. This doesn't just lower the clock of its components, but as well it's voltage, being possibly more effective than rovclock (since the documentation for these cards has been released to the public I hope to see this functionality in the free sometime soon).
That's it. Sorry if you already knew all this, but I felt like writing it for it would save me a lot of time had I found something like this a year or so ago. I can assure that my laptop really is quiet now.
PS. If you feel like expending a bit more of time, you can as well undervolt the CPU. This has no negative consequences as far as I and others can tell. Its effects are very, very impressive too. Learn about it in the following links, and if you want me to tell you my settings just ask me:
http://phc.athousandnights.de/
Hope this helps.
J.
PS1. As for the '75 C' temperature reading, I'm almost sure it's hard coded, so it's either '75'='fine' or 'something else'='bad'. That's why I don't think that fiddling with the fan set points is of any use. Let the kernel/BIOS/whatever do its job.
PS2. The 'quiet' button just forces the CPU to 600 MHz, and hence you usually get lower fan speeds. But it's quite useless for you don't really want to have your laptop running at a fraction of its capabilities. What is needed is a good frequency scaling and optimised power behavior, not a limited proccessor.