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Disabling CPU fan management in Windows XP

I have an hp nx6120 running XP Pro and the latest BIOS. Recently it started dislplaying a lot of odd behavior (keyboard not working, shortcuts would open the properties window and not the application or folder) and I narrowed it down to an overheating issue.

At first I thought it was the fan, but I noticed that when I'm in the BIOS, the fan runs constantly. I also have a Puppy Linux CD that I booted to and found that the fan runs all the time.

When I boot into Windows, the fan cuts off as the Windows splash screen comes on and is off most of the time. It does turn on sometimes, but not much.

When I'm in Windows and I start having the above issues, I apply a light vacuum at the fan vent to force the fan to spin. Within 20 seconds or so, all the problems go away.

I've installed SpeedFan. The Remote Temp and Temp1 often go over 50 degrees, but then fall seconds later by 5 or 6 degrees. I do notice the fan working when it gets to that temp.

My theory is that the sensor or sensors on the motherboard are sending back incorrect temperature data, showing the CPU to be cooler than it really is, thus Windows doesn't feel it necessary to turn the fan on, causing the odd behavior.

So my questions are:

Does that sound like a plausable theory?

Appart from replacing the motherboard, is there a way to completely disable Windows from messing with the cooling fan so that it runs all the time? That would solve the problem much more cheaply than replacing the motherboard.

Thanks for your help.

G
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Alex Appleton
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Go and get a program called speedfan.  You can manually control the speed of your fans using this program.
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schvankus

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I did install SpeedFan as per my original post. However, under the Fans tab, there are no fans to configure.
>>  Recently it started displaying a lot of odd behavior   <<  sometimes updates and other install may influence the behaviour.
you can try a system restore to a previous date, or (after a backup) a reset to factory status (from the recovery partition)
if you like to go hardware - you can clean the haetpaste off the cpu, and replace it with arctic silver : http://www.arcticsilver.com/

replacing the fan  (or cleaning it) can help too
Thanks for your response.
I had already tried a clean install with an SP3 disk. That didn't work. Then I tried another clean install with an SP2 disk. Same issue. I feel that would rule out a software update as the culprit.

I had a second CPU and tried that. I cleaned the the heatsink and CPU and applied new thermal compound. It seemed to be a bit more tolerent, but eventually I saw some of the odd behavior again.

The fan isn't the issue as it runs absolutely fine. The problem is how it is managed. Windows must be getting info from the motherboard through ACPI that says the CPU is cool enough, and shuts off the fan. The CPU must be hotter than that and starts causing issues.

My feeling is the problem is with the temperature monitoring on the motherboard. That's why I was looking for some way of telling Windows to ignore all temp info coming from the motherboard and let the fan run. Maybe that's not possible.

Thanks again for your suggestions.
>>  I was looking for some way of telling Windows to ignore all temp info    <<   the only way i know is from the bios

you can set the control panel>energy settings to max prestations in
I tried setting it to Presentation and it still had those issue.

Thanks for the suggestion.

i doubt you can disable the fan, as this would lead to overtemperature of the cpu quickly
nobus, i'm not sure you understand what i'm trying to achieve. i do not want to disable the fan, i want to stop  Windows from trying to manage it. The motherboard runs and manages the fan fine. Windows takes temp data from the board and decides when the fan should run. I just want it to be managed by the board with no input from Windows.
when you are running Windows, it is running the fan, as you say. so if you could disable that; you would have NO fan...
i see. i guess what i don't understand is that in Linux, the fan runs all the time. does Linux not use power management? Windows actively manages the fan speed and I was looking for a way to stop it from doing so and just let the fan run. When I'm in the system BIOS, the fan just runs and runs, so obviously, at a hardware level, the fan doesn't need any input from an OS to work. if there's no way to do what i'd like to do i'll accept that as the answer and award you the points.

thanks for all your help.
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thank you for all your help, nobus. i think i have a better undstanding of what's going on now. i especially liked the last link about changing voltages to alter fan speeds. i've always used a resistor to slow the fan in systems i've built. this is a much better way of achieving the same thing. thanks for passing that on.

thank you all who took the time to respond to my question. it's much appreciated.