How is the case fan in a Dell PC regulated? Can this setting be tweaked?

[himmatsj]

I am experiencing something rather weird. On my older PSU, my idle/light usage case fan speed was 1100-1200RPM, but for that same fan, on my newer CPU, the idle/light usage fan speed is 1500-1600RPM. This is a good 25-33% jump, and it is very audible noticeable.

Thing is, temperature wise, both before and after it is similar. My CPU temps for example are identical. I am monitoring temps with HW Monitor.

What can be the cause for this? How is the fan RPM determined? How can I tweak it? I believe currently it is over-working itself and I would like to test if my hypothesis is true.

The PC is a Dell Inspiron 660.

Thanks!

 

[Rogue Leader]

So there is a temp sensor on the motherboard that controls it. You MAY be able to adjust it in the BIOS but not likely, otherwise you're SOL. Now it may be running faster because your new CPU runs a bit hotter so it does that to get the temps to the same range.

Also check to see that its not buried in dust, Dell's intricate intake setups tend to get clogged.

 

[himmatsj]

Do you know what TMPIN1 sensor refers to? It seems to be stepping up/down in accordance to this particular sensor. I know TMPIN2 is for the CPU, cause they correlate very strongly. What could TMPIN1 be? If I know this, I can have an idea as to what's causing the higher temps, thereby causing a higher case fan speed.

 

[Rogue Leader]

TMPIN1 is likely your chipset or motherboard temp sensor.