I just bought and installed a new 80mm case fan in my PC today
(putting it in the back of the system case). It connects via a 3-pin
connector on the motherboard. The thing is, when I first turn on the
PC, the fan spins fine, and then seconds later it just comes to a dead
stop.

I am a bit worried that the fan would just stop like that, seconds of
turning on the PC, and it hasn't seemed to come back on again.

I noticed that one of the features on the 80mm case fan states that it
is "Computer Controlled". Would that explain why the fan would just
stop within seconds of turning on the PC? Am I right in guessing that
this fan will only turn on as needed, if the PC gets hot enough? And
it will adjust its fan speed as needed to cool the PC, once it turns on
(not fixed at a set speed once turned on)?

I have also notice that the main CPU fan on the heatsink seems to have
the ability to adjust its speed, too. It will turn fast and loud at
first when turning on the PC, but it slows down and quiets down within
seconds of turning on the PC.

Any input, please?

What happens after several hours of heavy use? So far
you've described an advanced case of normal.

<ltf4522 (AT) yahoo (DOT) com> wrote

I don't think I've yet seen or heard the fan turn on, even after
several hours of use (nor hear the main CPU fan start to spin any
faster in case the CPU is getting more taxed, and hence more hot). But
I'm not really taxing the system with just casual web browsing. The
fan (80mm case fan) always turns on for a few seconds after bootup, but
then turns off right after those few seconds after bootup. The
processor is a Celeron D 335, if that matters. So, it's normal for the
80mm case fan to stay off like that?