SPCR

This may be a totally newbie question, but here goes...

I have an Asus p4p800 E Deluxe motherboard. According to the info on the speedfan website, it should be supported for fan speed control. I have enabled Qfan in the BIOS, but I thought this was only important for CPU fan control?

Nevertheless, when I turn down the percentages for fan1-3 speeds, nothing happens... What am I doing wrong?

best regards
Knut Inge

Try to disable q-fan in the BIOS.....it may be interferring with the Speedfan program.

I assume you have read the Speedfan documentation....it's very complete and should explain everything.

Yes, Q-Fan will interfere. If you wish, you can leave it on during bootup and disable it when SpeedFan loads up by going to Configure > Advanced, select the chip that controls the fans, and change the "Thermal Cruise" options to "Manual PWM Control".

Thanks guys. Will check it when I get home.

regards
Knut Inge

I switched off Q-fan and now I can regulate the CPU fan, but not the two system fans tapped from the remaining fan headers on the mobo. Also, the monitoring seems to be way off. My Zalman 7000 is slowed down by the fanmate to its minimum, 1200rpm reported in speedfan. When I lower its speed even further in speedfan, it reports 14000rpm!

with regards
Knut Inge

Common problems......only one of your fan headers is wired for speed control, and there is a lower rpm limit the board can detect. Go lower and the read-out is unstable.

Some boards do not have these problems. In your situation there is probably no solution, other than going to a separate fan controller.....

Seems that you are right

http://forums.anandtech.com/messageview ... y&arctab=y


"..Since then, it has been marvelous. It has been my ASUS P4P800 instead that has fallen short of expectations, since they only implemented full fan-control for the CPU_FAN header despite the potential resources of the Winbond super-IO controller chip on the board..."


So now my other option is using the fanmate for running the Zalman 7000 at a constant low speed, and using that CPU fan header for software-controlling one of the system fans. The other fan? Either disable it, or run it at a constant 5 V. How easy is it to run fans in series? I mean tapping the variable voltage from fan2, and divide it amongst the two system fans. May cause speed readings to fail, but I cant see why it should not work? Id rather have two slow fans than one faster.

Anyways, thanks for the great help, guys
Knut Inge

BTW, what is a general "sort of optimal" temperature to fan speed formula?

I envision something like:
if (all temps < 40 deg C)
all fans off
else
if (50<CPU_temp<70)
CPU_fan scale linear from (temp-50) to 70
if (system_temp OR HD_temp > 40)
System fan scale linear from (temp-40) to 55
if CPU_temp > 70
all fans at 100%
end
end

(In my system, I would have to have only one fan speed output of course

You can use one MB header to control two fans. That's running in a parallel configuration, not series. You can buy "Y" splitters to do this. Be certain the total amp draw for the two fans, does not exceel the MB specs.

I cant see how running two fans from one MB fan header is inherently "serial" or "parallell"? It is the electrical connection between those two fans + MB (ie the splitter) that decides if you are running in series or parallell.

Knut

Not exactly. Here's a parallel setup.....MB has a Red(positive) and a black(negative) header. Forget the yellow. Run the red to the fan red, and the black to the fan black. Then run the first fan red to the second fan red, and the first fan black to the second fan black. Both fans are wired parallel, running on 12V.

Here's a series setup......run the MB red to the first fan red. Run the first fan black to the second fan red. Run the second fan black to the MB black. Each fan is wired in series, running at 6V each.

Simple, huh....

I`m an electronics engineer and I DO know the difference between serial and parallel

I am objecting to you saying that "You can use one MB header to control two fans. That's running in a parallel configuration, not series". That is wrong. One fan header could run two fans in either parallel or series configuration =) Which is better is an open question...

with regards
Knut Inge

Well yeah.....but if you attach two fans to the MB using a "Y" splitter it'll be parallel, with both fans at 12V.

To get a serial fan setup off the MB, you'll need to wire it differently like I stated.