"12V" is actually a modulated "square/rectangular" wave whose duty cycle is determined by the sense leads input telling if more [or less] cooling is needed. More cooling needed the on time of the 12 volt gets longer each cycle.
I know nothing about how speed fan provides its control of a number of fans.
IF the temp you are reading, is valid you are in great shape and could cut the CPU's HSF fan speed quite a way down.
I just had my mother board replaced (P4, 3 GHz). The old "HP" board's fan was very, very quiet.
Although the tech said he used the same fan on the replacement board, it now sounds like a hair dryer! He said just buy a quieter fan.
First, why would the same fan be so much noisier?
I read the article in PC Magazine about "Quieting Your PC," downloaded the program "SpeedFan," and installed it.
I think I followed the steps correctly. I can monitor the fans speeds (3 fans) and the CPU temp, plus two other system temps (whatever they are), but the program does not seem to be controlling the CPU fan speed.
SpeedFan is supposed to start at bootup, but I don't think it is. How do I get that program to run at bootup?
System info: Pentium 4, 3 GHz, Hyperthreading, Mother Board is a FOXCONN 661 (SIS-661) with Phoenix BIOS LTD6.00. CPU temp after a few hours is 24 degrees C, and fan speed is 4400 ROM.
In the User Manual there is a diagram of the fan plug pinout. It just shows "Gnd," "12V," and "Sense." Does that mean that there is no control, and that the fan runs at full speed all the time?
Is there a chance that I can control fan speed, or should I just try to buy a quieter fan?
Thanks in advance,