Laptop fan making the CPU work ?

[Dunga Bee]

Hey everyone. I have an interesting question/problem on my hands.

I have a P3-500 laptop running Win2K.

I've noticed that if I'm using the laptop in some high CPU activities for a while the CPU exhaust fan kicks on, as expected. Now the strange part...

When the fan comes on, even if I close EVERY app that's running on the CPU, the CPU still stays at 50-80% all the time. Looking at task manager shows that the 'System' service seems to be the main culprit here.

Has anyone else seen anything like this ?

Of course if I close all apps prior to the fan kicking on the CPU will rest at 1-3%, like normal.

Thanks for yout input.

[Zuzzz]

Could the CPU be throttling itself back thus throwing the readings out of whack? I ask this as I know some CPUs in laptops do this. What effect it has I personally havent seen. What you said here suggests this possibility.

[Dunga Bee]

You could be right. I know I've seen the CPU throttle back to 1/2 power on a low battery, but I've never checked when the fan was on. I'll run WCPUID the next time and check it out.

I am a bit skeptical on this only because when I do stop all the open programs and such, I'd still expect the CPU to drop down to very low CPU%, even throttled, since it's not doing anything. But it still seems to stay over 50% all the time once the fan is on.

Thanks for the idea and I'll let you know what happens.

Any other thoughts from the crowd ?