Why is my Compaq NC8430 laptop so darned HOT?
Turns out that with the ATI Video drivers for that laptop, for Vista, the GPU was always turned up high. Even if the CPU was doing nothing. And this generated lots of heat.
I guess this is to take advantage of the fancy graphics in Vista, but I wasn't using the graphics. I just wanted a cool, quiet laptop.
I went into the ATI "Catalyst Control Center":
...and turned on the PowerPlay feature. This is a way you can turn down the GPU administratively.
By setting it to "max battery life" even when plugged in, the computer was no longer hot. The CPU temp is now 50C, and the fan is quieter.
It's now no longer melting the stickpoint things, too.
EDIT: After I lived with it for a little, I decided that the fan was still too loud, still running too fast for the temperature. Someone suggested a BIOS update - I've got the latest BIOS. But while investigating, I learned about the ASL Compiler from Microsoft, which lets me set the fan speed for various temperature ranges. It also lets me set the temp ranges themselves. I followed Eddie's advice, changing it for the nc8430.
Now I wouldn't recommend this for everyone, but for superusers?
What I did was adjust the fan-speed % and the temperature brbeakpoints. Now the fan runs at 20% speed (v quiet) when the CPU temp is 50C.
I used a quick .NET Program to export the DSDT data. Find it here.
I also took one further step - and that was to reduce the CPU voltage via RMClock. I don't know if this made a big difference or not. But I honestly don't often do CPU intensive things on the laptop. I don't need the CPU running at max speed.
With all these changes, it's like a brand new laptop.
I hope this helps.
Maybe thermal paste between CPU and heat sink has dried out? If so, you will need to disasseble your notebook, carefully remove heatsink reaply new thermal paste, and assemble your computer. See my reply here
LG R500 Notebook crashing
BTW: get service manual before disassembly - you can probably google it.
Some (or many, depending on who you ask) laptop brands have pretty faulty ACPI tables. Windows XP was very lenient with those kind of things and handled many things on its own even if they were not correctly specified. But Vista started to adhere to them more precisely which is nice if ACPI is correctly done in the hardware but downright sucks if it isn't. Hardware vendors weren't quite forced to look after these things because they somehow worked.
A BIOS upgrade might solve this, but in many cases there is no easy solution (short of reinstalling XP again) because the vendor already got all the money they are going to get from you so why should they care?
A friend of mine had an issue with his ThinkPad T40p where the fan would only kick in after the CPU reached around 95 °C which was not a nice temperature to keep the laptop on your lap.