Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

Could someone tell me why the CPU fan runs at 5300 rpms all the time when
using the mb. I replaced an intel motherboard with the P4VP-MX and now the
CPU fan runs full speed all the time. I tested the fan on another pc with
the Intel mb and it works fine.....running at slow rpms. I have looked
through the BIOS to see if there is a way to slow the fan but had no luck.
Is there something I am missing, or should I look at purchasing a fan speed
control. Thanks for the help.

Bezerk

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <5XPJe.15138$3S5.34@tornado.rdc-kc.rr.com>, "Bezerk"
<adsf@adsf.com> wrote:

> Could someone tell me why the CPU fan runs at 5300 rpms all the time when
> using the mb. I replaced an intel motherboard with the P4VP-MX and now the
> CPU fan runs full speed all the time. I tested the fan on another pc with
> the Intel mb and it works fine.....running at slow rpms. I have looked
> through the BIOS to see if there is a way to slow the fan but had no luck.
> Is there something I am missing, or should I look at purchasing a fan speed
> control. Thanks for the help.
>
> Bezerk

First of all, the Intel retail fan is sensitive to the air
temperature inside the computer case. If the case your P4VP-MX is
in, is poorly ventilated, it could be the case temp has risen above
38C or so, at which point the fan could be running at max speed.
The temperature sensitive fan ramps up in speed, between temperature
T1 and T2 (the set points have varied a bit from product to product,
so download the datasheet for your processor from the Intel site
to get the exact temp points - it might be 30C and 38C for example).

To achieve control over the fan speed, one simple method is to
drop the voltage to the fan. As you observed, purchasing a
fan speed control will fix the problem.

Your motherboard does have a hardware monitor chip, and I expect
it has at least a couple channels of fan control. The gating
item for a hardware monitor chip, is the presence of an external
buffer transistor for each controlled fan. Looking at the picture
of the P4VP-MX in the downloadable manual, I can see a big transistor
and capacitor next to each fan header. Even though the manual
makes no mention of Q-fan or Q-fan2, there is a remote possibility
your fan can be controlled for you.

Get a copy of Speedfan from almico.com/speedfan.php and see if
Speedfan sees your hardware monitor chip. If the transistors I
see in the picture in the manual really are connected to the
fan controller channels, maybe you'll get the control you desire,
without buying a separate controller. Speedfan cannot tell if
the buffer transistor is present, so even if Speedfan finds and
programs the monitor chip, only you will be able to tell if
it is working or not.

Paul