Re: CPU fan has 4 wires. Mobo header has 3 pins. Suggestions?

 
<snip>

http://www.winbond.com.tw/NR/rdonlyres/20CA693C-F2AD-48CF-8F25-15223D71BB25/0/W83697HF.pdf

With the capacitor across the fan, it doesn't seem that a square pulse
would be applied to the fan but instead a ramp up voltage.  I'm
assuming the cap discharges before the next pulse (on state).  My
guess is that they don't want a high current in the winding of the
motor in the fan which could burn it out when it hasn't started moving
yet or is just getting pulsed to speed up again.


I've been using SpeedFan in my latest host since it came out, and it
replaced MBM (MotherBoard Monitor).  Don't know how many years that
I've been using those programs but I have yet to replace a CPU fan.
Fact is, I would prefer having to replace the CPU fan after several
years rather than have to constantly listen to the high noise with it
spinning always at full speed but when it provides no additional
cooling (i.e., when the CPU temperature won't go down after exceeding
a certain RPM).  The BIOS will slam down the CPU if it gets too hot so
I'm saved and will then have to replace the CPU fan.

Many folks are deluded into thinking they need their CPU running at
its absolutely attainable lowest temperature using the current cooling
method.  They forget that the CPU is rated for continuous operation
at, say, 80C but they've been told to get it somewhere around 45C.  I
have seen some that became unstable at 60C.  I have Speedfan
configured to pulse the CPU fan at 5% duty until it gets to 55C where
it will then up the fan speed to get it below 55C and alert me if the
temperature exceeds 60C.  Fact is, for my setup, I know it will run
reliably at 72C but I'd prefer a safety margin.  It only hits 55C when
I'm playing a game but the noise of the game swamps the noise of the
increased RPM of the fan; else, I'm so into the game that I don't
notice the increased fan noise.  Of course, whether I can continue
using Speedfan depends on whether it recognizes the controller in my
new host.

Thanks for the links.  Makes for some interesting reading.  Hopefully
the 4-wire fan connected to the 3-pin header (which means power,
ground, and sense are connected but not the PWM wire) will have the
CPU fan always spinning at its max speed - until I get around to
replacing it.