P4C800 CPU fan speeds

[electro]

I have a P4C800 Deluxe motherboard and an intel 3.0 gig CPU retail
version with the fan and heat sink that came with the CPU. Used the
heat sink paste that came with the CPU and fan heatsink combo. My
question is what temp should the cpu run at and what speed should the
fan run at. It is connected to the motherboard cpu fan connector . I
find that the fan is quite noisy. At 32 C fan speed is 3750 but at 34
C the fan speed is above 5000 and quite noisy . Anyone else seeing
these kinds of temperatures and fan speeds. How can I correct this
problem. Have been told by my local computer store where I bought the
components that the Intel fan and heatsink are very good procucts
which match what I think myself. Could the motherboard CPU fan speed
controller be the problem or is it just the way things are to have
these high fan speeds. Tried Qfan and it shut the fan off and the temp
went to 54 C so i promply turned off Q fan.
Thanks for any help.

 

[Paul]

I have a P4C800 Deluxe motherboard and an intel 3.0 gig CPU retail
version with the fan and heat sink that came with the CPU. Used the
heat sink paste that came with the CPU and fan heatsink combo. My
question is what temp should the cpu run at and what speed should the
fan run at. It is connected to the motherboard cpu fan connector . I
find that the fan is quite noisy. At 32 C fan speed is 3750 but at 34
C the fan speed is above 5000 and quite noisy . Anyone else seeing
these kinds of temperatures and fan speeds. How can I correct this
problem. Have been told by my local computer store where I bought the
components that the Intel fan and heatsink are very good procucts
which match what I think myself. Could the motherboard CPU fan speed
controller be the problem or is it just the way things are to have
these high fan speeds. Tried Qfan and it shut the fan off and the temp
went to 54 C so i promply turned off Q fan.
Thanks for any help.

You can download an Intel datasheet for the P4, and the datasheet
has some information on what the fan in the "boxed retail" product
does. For example, for the 3.06GHz processor, fan speed ramps between
32C and 40C, and the HSF measures the _air_ temperature. So the design
intent of the Intel solution is to give you "constant cooling effort"
rather than "constant die temperature". The fan is only adjusting
its speed to compensate for the smaller delta T.

http://developer.intel.com/design/Pentium4/datashts/
http://developer.intel.com/design/pentium4/datashts/29864310.pdf

Some guys in the following thread try to defeat this feature, by
partially shorting the thermister inside the fan body. Of course
this isn't what you want, because the fan runs at full speed all
the time. On the other hand, if you did this mod, you could then
enable Qfan, as the fan would be getting full voltage due to the
defeat of the thermister, and then Qfan would attempt to maintain
a constant die temperature (i.e. goes faster when die temperature
rises). Before doing this, make sure that Qfan can supply the
amount of current that the Intel fan has printed on it.

http://forum.oc-forums.com/vb/showthread.php?s=&threadid=121331

So, to determine whether the Intel fan is working correctly, you
would have to compare the _motherboard_ temperature to the
measured fan RPMs, because those two should correlate. When the
die temperature rises, it will take a while for the air temperature
to rise, so the Intel method should give a slow ramp over a matter
of minutes. Qfan, on the other hand, should ramp in seconds, as the
die temperature can shoot up quicker than the air temperature.

Another way to fix this, is to find a way to keep your case air
temperature lower. This means adding additional low RPM, high volume
fans, so you won't be adding too much to the noise. The best place for
fans is on the back of the computer, as then the noise is further
away from you. I've seen at least one picture on the web, of a case
that someone cut a hole for a 120mm fan on the back. That can move
more CFM of air than an 80mm, for the same perceived noise level.

HTH,
Paul

 

[electro]

Is your machine in an older case by any chance? One without an extra fan or
two in it? I have exactly the same hardware you describe and my machine was
extremely noisy until I moved it into a new aluminum case with fans on back,
front, and top. (It was the temp/fan speed that was the culprit, not any
noise dampening properties of the case itself -- with the added air flow in
the new case, or with the cover removed in the old case, the CPU fan runs
steadily at about 2850 RPM where before it ran at 5100RPM.)

This is my first P4 and I simply hadn't realized that much more attention
has to be paid to cooling than with previous processors. Maybe you're having
a similar awakening?

Thanks for the replies. The case is an antec tower and I had two extra
fans mounted in the back for case cooling . I have added two more ,
one in the front and one at the top of the back and now my cpu fan
speeds are in the low 3000 range and much quieter. The speeds for the
fan were allright until I put the side cover on and then the fan went
crazy. I think my problem is solved. Again thanks for the replies.
Electro.