The fan is set to silent in EFI, but it still runs at 1000 rpm. Is this the lowest it'll go?
In Speedfan, the CPU temp is shown as 86C (idle) but the Core 0 and 1 temps are 40C. I guess the CPU temp is wrong, but why? In EFI the CPU temp is fine.

Drive the fan with non-pwm electricity and control the fan speed with voltage. Set it at whatever speed you want and run it at the constant speed.

To get a solution, or at least an understanding of your problem you need to do the following.

Update speedfan and see if the "CPU" temp is different.

Update the BIOS, it may be a bug (check your BIOS version first as well as the latest version on their website).

If those don't help, then check whether the fan control is set to 3-pin, or 4-pin or auto, this can make a difference.

Lastly are you running the fan straight into the motherboard or through a controller or adaptor, as that can mess things up.

If you don't get anywhere follow what "ces" says.


Andy

How do I control the voltage with this motherboard? Shouldn't PWM just work?

I've already got the latest stable SpeedFan: 4.46. Will see if the BIOS can be updated. Where do I find the 3 v 4 pin setting in the BIOS?
It's connected straight to the motherboard. RPM control does work, but it doesn't go low enough.

I would test if speedfan is the problem: if you're in the BIOS and have the CPU fan profile set to manual, you can adjust the fan settings down to 20% (or lower, if your temps are low enough). If it's fine, I'd just uninstall speedfan since it doesn't seem to be reading CPU temps correctly. If not, then maybe your fan just can't go below a certain speed using PWM, and you'll either need a new fan, or manually adjust the voltage as ces suggested.

Sorry, what I said was incorrect. Its described in the BIOS as "PWM" or "Voltage" in reference to how the fan is controlled, the difference being that 4-Pin fans use PWM and 3-Pin fans don't. If you have a 3-Pin fan plugged into a 4-Pin connector it will work, but many don't play well when the BIOS is set to PWM and therefore it might be better to set it to "Voltage" in the BIOS.


Andy

My BIOS doesn't have that option.
The HSF is a stock one from Intel Pentium G620.

1. Probably yes. PWM fans usually have some min speed. Search spcr for more info.
2. Because the manufacturer has not given all the technical information to the author of Speedfan.

You might have to do a bit of "old school" testing.

Open speedfan, run something CPU intensive, bull the CPU fan cable out, stick your fingers on the CPU heatsink and compare the heatsink heat with what speedfan says, once its nice and toasty (uncomfortable to touch for more than half a second) then plug the CPU fan back in and make a note of the fan speed.

That will tell you the maximum fan speed, google (or check SPCR) to find out what the maximum fan speed is supposed to be for that fan, if that matches what speedfan is reporting then you know that the fan speed that speedfan is reporting is correct.

Once you have done that you will know enough to make some decisions.

You should know whether speedfan is reporting the fan speed correctly, you should be able to identify whether that high temperature that speedfan is reporting is correct or not via "finger burning" as well as whether that temp rises inline with the other CPU temps or not (in speedfan), if it does not then it is bogus and you should ignore it.

That only really leaves 2 directly related points, does the CPU heatsink/fan cool enough for your needs and is it quiet enough.

Both of those points can be addressed by either replacing the heatsink/fan with something that is better/quieter, or make the exiting CPU fan quieter by another method.

I hope this helps.


Andy

Here is an approach you can use that will permit you to use a larger, slower quieter fan on your existing heat sink:
viewtopic.php?p=539859#p539859

I wish this was handled via normal drivers, then not every app would have to reinvent the wheel.

Disabling fan control tells me the max rpm is about 2000 rpm. The BIOS reports normal temps and rpm, so this one Speedfan temp is bogus.

The standard HSF cools properly and I think it's quiet enough. My HDD makes too much noise. :p

I think that 1000rpm is indeed the lowest the fan will go. A thousand rpm may sound like a lot but it`s a fairly low speed for a fan of this size. A good 92mm fan at this speed should be comparable to a 120mm fan at ~600rpm when it comes to noise.

Same thing with Asrock H61M-GS EFI's and a Freezer7 pro. It spins as low as 950rpm at idle, even if the same PWM fan would spin lower on an Asus skt775 board (I don't remember the exact value, but it was in the 600-700rpm range). I hadn't luck using Speedfan.

For instance, the older Freezer64 Pro PWM fan (skt 939) would stop spinning if the temp was lower than a desired value. I never managed to reproduce such behaviour.

With an Asus motherboard like this one it is not difficult to establish how low a fan will go. Fan Xpert is provided as part of the free AI Suite II download from Asus, and this includes a facility to calibrate the CPU fan at the click of the button. More than that it will display a graph showing where the current fan speed and % duty cycle is in relation to the Q-Fan mode that has been selected in the BIOS. For most PWM CPU coolers just setting the Q-Fan mode to the Silent profile in the BIOS will be enough to get the lowest CPU fan speeds. By using Fan Xpert you can calibrate the fan and see how this profile will react under load and/or higher system/ambient temperatures. If the BIOS setting doesn't give what you want then a custom profile can be created in Fan Xpert.

Where does one download just Fan Xpert (at the Asus site)? The Asus site is such a mess.

You have to download the whole of the AI Suite which is listed under Utilities http://support.asus.com/download.aspx?SLanguage=en&p=1&s=39&m=P8H61-M%20LE&os=&hashedid=kMLFhm2eGuxijgcI

Thanks. 1021rpm at 0% and 20%, 1000rpm at 10% and 2360rpm at 100%. Standard and Silent profiles are nearly the same. It's a cool toy to play with. :p