It does look like your motherboard does have the ability to vary the speed
of the CPU fan, depending on how hot the CPU is.  I wouldn't be surprised if
the power supply fan is also thermally controlled.  This is why things don't
really overheat, when the case is closed, but the fans get considerably
louder.

I'm guessing about what exactly the Intel specifications mean.  Perhaps the
73w thermal guideline is meant to give system integrators an idea of how
much heat they need to dissipate from the CPU.  The 67C thermal spec may be
a maximum that the processor should be kept below for safe operation.
Perhaps setting the BIOS CPU temperature alarm to 60 or even 65C would be
good.  I think it will need to quite high because the processor will get
quite warm under full load, even with good case ventilation.  Keep in mind
that the Prescott processors have a kind of speed step capacity; they will
underclock themselves if they get too hot.  While this means you processor
won't overheat, it also means that it won't be working at full speed.  I'm
not sure at what core temperature this feature kicks in.  Maybe someone more
familiar with the Prescott Pentium 4s can add more.

Since adding a fan to the case sounds like it would not be too difficult, I
would at least try that.  Based on the results of doing this, you can better
decide whether a new case will be necessary or not.

While the CPU is under some load while you are in the BIOS, I don't think
this load is 100%; so, keep this in mind when you are considering the
significance of the temperatures that you see there.

John Sproule

----- Original Message -----
From: "Venkat Viswanathan" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, March 04, 2005 2:16 AM
Subject: [PCBUILD] fan noise


> i took the advice of all and went into bios and noticed the following:-
>
> (1)with the side panel open(10minutes observation)
>
> mobo temp.--39/40 deg c
>
> cpu temp---47/48 deg c
>
> cpu fan speed--- ranged between 3792 rpm to 4115 rpm
>
> system steadied at bios at cpu=48 deg c and cpu fan=4218rpm not static at
> these figures but hovering around them
>
> (2) side panel closed (10mts.observation)
>
> mobo temp---40/41 deg c
>
> cpu temp---49/51 deg c
>
> cpu fan speed-- ranged between 5037 rpm to 5357 rpm
>
> steadied at cpu=5
> 0 deg c and cpu fan= 5273rpm (was hovering around these figures)
>
> i went to intel site and checked specs. for my processor (espec no SL7C4)
> and among other things found:-
>
> thermal guideline=73.0W
>
> thermal spec=67deg c
>
> i shall be grateful for any help in understanding "thermal guideline" and
> the
> "w" (watts?) and also does the thermal spec. mean that the processor can
> reach upto 67 deg c safely?
>
> in my bios there is a cpu temp. warning feature which is disabled at the
> moment because i do not know what fig. to input. (it lists 50deg c
> upwards)
>
> depending on the forum's input i will set the cpu warning and also
> consider a
> case fan for which there is a provision in the mobo and also an opening at
> the back of the case.

               The NOSPIN Group Promotions is now offering
              Mandrake Linux or Red Hat Linux CD sets along
             with the OpenOffice CD...  at a great price!!!
             http://freepctech.com/goodies/promotions.shtml