Reliable CPU fan speed controller?

[JD]

I have a CPU fan that runs all the time at around 4,100 rpm.
This is completely unnecessary when the weather is cool. I believe a speed
of about 3,000 should be ok at present.

Is there any such program around? I know about SpeedFan but I think
it's a primitive piece of work. The CPU needs a delicate touch.

I did a search and found
http://wareseeker.com/free-cpu-fan-speed-control-software/
However it's hard to tell whether they are discussing the cpu speed or
the fan speed.
Anyone have experience of these?

TIA

 

[Paul]

I have a CPU fan that runs all the time at around 4,100 rpm.
This is completely unnecessary when the weather is cool. I believe a speed
of about 3,000 should be ok at present.

Is there any such program around? I know about SpeedFan but I think
it's a primitive piece of work. The CPU needs a delicate touch.

I did a search and found
http://wareseeker.com/free-cpu-fan-speed-control-software/
However it's hard to tell whether they are discussing the cpu speed or
the fan speed.
Anyone have experience of these?

TIA

Have you looked at your BIOS functions ? Maybe there is
an option in there to control the fan.

Paul

 

[JD]

Have you looked at your BIOS functions ? Maybe there is
an option in there to control the fan.

Paul

Great suggestion Paul.

I looked in the BIOS and found 2 options for the fan
Fan Control - [Enabled}
Lowest Fan Speed - [Slow]

The first one had no speed control as far as I could see and was the
existing
setting since the motherboard was installed
I set it to the 2nd one and rebooted.
It was exactly the same as before - whizzing along at 4,100 + or - a few
hundred.

I did have this fan plugged into the right socket - it is right beside
the CPU.
I looked in Control Panel - Add-remove hardware and it was no help.
Likewise in the Control Panel itself.
Do you know of any other possible location for a fan speed controller?

TIA

 

[Paul]

Have you looked at your BIOS functions ? Maybe there is
an option in there to control the fan.

Paul

Great suggestion Paul.

I looked in the BIOS and found 2 options for the fan
Fan Control - [Enabled}
Lowest Fan Speed - [Slow]

The first one had no speed control as far as I could see and was the
existing
setting since the motherboard was installed
I set it to the 2nd one and rebooted.
It was exactly the same as before - whizzing along at 4,100 + or - a few
hundred.

I did have this fan plugged into the right socket - it is right beside
the CPU.
I looked in Control Panel - Add-remove hardware and it was no help.
Likewise in the Control Panel itself.
Do you know of any other possible location for a fan speed controller?

TIA

Maybe the next test, is to try Speedfan. If Speedfan cannot get any
response from the fan, then it could mean there simply isn't
a hardware feature there to control the speed with. (It could mean,
for example, that you've mixed incompatible components together.
Or that the motherboard makers are cheapskates.)

The rest of this is some background. Mixing a three pin fan with
a four pin fan header, may deprive you of a control method. And
that is an example of how you can accidentally be stuck with
a screaming fan.

*******

The CPU fan header has a couple features to control fan speed.
Back in the "three pin header" days, voltage control was used.
The fan normally runs from 12V. But the motherboard could control
the voltage, and deliver a variable voltage between 7V and 12V.
This would take a PWM output from the controller, and require a
MOSFET or transistor near the fan header, plus a capacitor,
to convert the pulse width modulated control signal, into
a voltage. It costs the motherboard maker some money to do that.

X <--- RPM (from fan to motherboard, for monitoring)
X ---> 7 to 12V to power fan
X --- Ground

If you're using Speedfan, Speedfan may find the registers that
control the PWM output. The register can be programmed, and
the hardware chip is then outputting a PWM signal. But if the
motherboard maker wants to save money, they don't bother to
install the interface circuit (the MOSFET and capacitor). Speedfan
cannot tell those components are missing. So one of the checks
I make, when someone has this problem, is to look at a picture
of the motherboard, and see if the appropriate looking components
are installed nearby.

(Some general rules of thumb. Prebuilt systems from HP/Dell/Gateway
are the ones most likely to have fan control per header. Which
means they have the most fan control of all. On an Asus motherboard,
the cheapest boards have no fan control. A board with QFan has the
CPU fan controlled. A higher end board with QFan2, has two headers
under control, one via CPU temp, one via chassis temp. So that should
give some idea what to expect in terms of working channels. With the
four pin fan header generation, you're much more likely to have a
CPU fan control, so the situation should be getting slightly better
as time passes.)

*******

The second control method, is of more recent design. Both
Intel and AMD now use four pin fan headers for CPU. The fourth pin
is (what a surprise) PWM. What is happening in this case,
is the responsibility for the MOSFET and capacitor, is now
up to the fan manufacturer, as they're inside the fan. The motherboard
has a fan controller interface on it somewhere (I can't say
right off hand, where this one is located now). The logic
signal output, running at perhaps 25KHz, is delivered on the
fourth wire of the fan. The fan runs at full 12V all the time.
The conversion circuit inside the fan hub, uses the pulse
width of the PWM signal, to control the voltage delivered
to the fan. That means the fan can run at 7V, using a
circuit inside the fan hub to make the 7V from the supplied
12V.

X ---> PWM (from motherboard to fan, 25KHz, indicates speed desired)
X <--- RPM (from fan to motherboard, for monitoring)
X ---> 12V DC (power from motherboard to fan)
X --- Ground

So as a consequence of having that fourth wire and control
method, Intel recommends not attempting to reduce the 12V
fed to such a fan. That recommendation, is so the MOSFET
has sufficient signal applied, so it will be biased properly.

Now, imagine what would happen, if you purchased an aftermarket
heatsink/fan combo, with a three pin connector, and connected
it to a four pin header. No PWM signal. No variable 12V.
And hence, no control method. Again, programs like Speedfan
will feel they're "dialing the knob", but nothing happens.

*******

There is one other feature, which was used in the past with
Intel fans. They had a thermistor in the fan hub. If the
computer case air temperature rises, the fan is set to
spin faster, based on the measurements by the thermistor.
That feature does not lend itself to control by the user.
Its purpose is to compensate for the worse cooling situation
caused by hot case air. So if the computer has poor ventilation,
the CPU fan may scream a lot more than it would in a cooler
running case. Any other control method applied, multiplies
its effect, by the effect provided by the thermistor. So if
the computer case was very cool, the fan may hardly be
turning at all.

Speed = Voltage_controlled_speed * thermistor_set_speed

Anyway, my next steps would be some Speedfan testing, and
some visual inspection. Like, checking whether there is a
three pin fan connected to a four pin header. On an older
motherboard, whether the appropriate components are next
to the three pin headers, and so on. As far as I know, there
isn't a programmatic way of determining whether the controls
are actually hooked up and working. A program could certainly
observe the RPMs, and notice that nothing is happening, but
I'm not aware of any program bothering to carry out such an
analysis for the user.

During the transition from three pin to four pin CPU fan
header, Asus made some motherboards with dual control
methods. The four pin header could be controlled as if
it was a three pin header. There was a BIOS setting,
that determined whether voltage control or PWM
control was used. And that means, on a small range of
motherboards, there is yet another BIOS setting to check
for. That practice was soon discontinued, in favor of
pure PWM control for four pin fan headers. Meaning
that the providers of aftermarket coolers, should
provide proper four pin fans, if they expected
satisfied customers. When you buy a retail CPU now,
from either Intel or AMD, you should expect to
find a four pin fan packaged with the retail CPU.

Paul

 

[JD]

JD wrote:
I have a CPU fan that runs all the time at around 4,100 rpm.
This is completely unnecessary when the weather is cool. I believe a
speed
of about 3,000 should be ok at present.

Is there any such program around? I know about SpeedFan but I think
it's a primitive piece of work. The CPU needs a delicate touch.

I did a search and found
http://wareseeker.com/free-cpu-fan-speed-control-software/
However it's hard to tell whether they are discussing the cpu speed
or the fan speed.
Anyone have experience of these?

TIA

Have you looked at your BIOS functions ? Maybe there is
an option in there to control the fan.

Paul

Great suggestion Paul.

I looked in the BIOS and found 2 options for the fan
Fan Control - [Enabled}
Lowest Fan Speed - [Slow]

The first one had no speed control as far as I could see and was the
existing
setting since the motherboard was installed
I set it to the 2nd one and rebooted.
It was exactly the same as before - whizzing along at 4,100 + or - a
few hundred.

I did have this fan plugged into the right socket - it is right
beside the CPU.
I looked in Control Panel - Add-remove hardware and it was no help.
Likewise in the Control Panel itself.
Do you know of any other possible location for a fan speed controller?

TIA

Maybe the next test, is to try Speedfan. If Speedfan cannot get any
response from the fan, then it could mean there simply isn't
a hardware feature there to control the speed with. (It could mean,
for example, that you've mixed incompatible components together.
Or that the motherboard makers are cheapskates.)

The rest of this is some background. Mixing a three pin fan with
a four pin fan header, may deprive you of a control method. And
that is an example of how you can accidentally be stuck with
a screaming fan.

*******

The CPU fan header has a couple features to control fan speed.
Back in the "three pin header" days, voltage control was used.
The fan normally runs from 12V. But the motherboard could control
the voltage, and deliver a variable voltage between 7V and 12V.
This would take a PWM output from the controller, and require a
MOSFET or transistor near the fan header, plus a capacitor,
to convert the pulse width modulated control signal, into
a voltage. It costs the motherboard maker some money to do that.

X <--- RPM (from fan to motherboard, for monitoring)
X ---> 7 to 12V to power fan
X --- Ground

If you're using Speedfan, Speedfan may find the registers that
control the PWM output. The register can be programmed, and
the hardware chip is then outputting a PWM signal. But if the
motherboard maker wants to save money, they don't bother to
install the interface circuit (the MOSFET and capacitor). Speedfan
cannot tell those components are missing. So one of the checks
I make, when someone has this problem, is to look at a picture
of the motherboard, and see if the appropriate looking components
are installed nearby.

(Some general rules of thumb. Prebuilt systems from HP/Dell/Gateway
are the ones most likely to have fan control per header. Which
means they have the most fan control of all. On an Asus motherboard,
the cheapest boards have no fan control. A board with QFan has the
CPU fan controlled. A higher end board with QFan2, has two headers
under control, one via CPU temp, one via chassis temp. So that should
give some idea what to expect in terms of working channels. With the
four pin fan header generation, you're much more likely to have a
CPU fan control, so the situation should be getting slightly better
as time passes.)

*******

The second control method, is of more recent design. Both
Intel and AMD now use four pin fan headers for CPU. The fourth pin
is (what a surprise) PWM. What is happening in this case,
is the responsibility for the MOSFET and capacitor, is now
up to the fan manufacturer, as they're inside the fan. The motherboard
has a fan controller interface on it somewhere (I can't say
right off hand, where this one is located now). The logic
signal output, running at perhaps 25KHz, is delivered on the
fourth wire of the fan. The fan runs at full 12V all the time.
The conversion circuit inside the fan hub, uses the pulse
width of the PWM signal, to control the voltage delivered
to the fan. That means the fan can run at 7V, using a
circuit inside the fan hub to make the 7V from the supplied
12V.

X ---> PWM (from motherboard to fan, 25KHz, indicates speed desired)
X <--- RPM (from fan to motherboard, for monitoring)
X ---> 12V DC (power from motherboard to fan)
X --- Ground

So as a consequence of having that fourth wire and control
method, Intel recommends not attempting to reduce the 12V
fed to such a fan. That recommendation, is so the MOSFET
has sufficient signal applied, so it will be biased properly.

Now, imagine what would happen, if you purchased an aftermarket
heatsink/fan combo, with a three pin connector, and connected
it to a four pin header. No PWM signal. No variable 12V.
And hence, no control method. Again, programs like Speedfan
will feel they're "dialing the knob", but nothing happens.

*******

There is one other feature, which was used in the past with
Intel fans. They had a thermistor in the fan hub. If the
computer case air temperature rises, the fan is set to
spin faster, based on the measurements by the thermistor.
That feature does not lend itself to control by the user.
Its purpose is to compensate for the worse cooling situation
caused by hot case air. So if the computer has poor ventilation,
the CPU fan may scream a lot more than it would in a cooler
running case. Any other control method applied, multiplies
its effect, by the effect provided by the thermistor. So if
the computer case was very cool, the fan may hardly be
turning at all.

Speed = Voltage_controlled_speed * thermistor_set_speed

Anyway, my next steps would be some Speedfan testing, and
some visual inspection. Like, checking whether there is a
three pin fan connected to a four pin header. On an older
motherboard, whether the appropriate components are next
to the three pin headers, and so on. As far as I know, there
isn't a programmatic way of determining whether the controls
are actually hooked up and working. A program could certainly
observe the RPMs, and notice that nothing is happening, but
I'm not aware of any program bothering to carry out such an
analysis for the user.

During the transition from three pin to four pin CPU fan
header, Asus made some motherboards with dual control
methods. The four pin header could be controlled as if
it was a three pin header. There was a BIOS setting,
that determined whether voltage control or PWM
control was used. And that means, on a small range of
motherboards, there is yet another BIOS setting to check
for. That practice was soon discontinued, in favor of
pure PWM control for four pin fan headers. Meaning
that the providers of aftermarket coolers, should
provide proper four pin fans, if they expected
satisfied customers. When you buy a retail CPU now,
from either Intel or AMD, you should expect to
find a four pin fan packaged with the retail CPU.

Paul

Thanks again Paul. I haven't read the above yet. Today I
used the Intel Active Monitor and it has a window called
Set Sensor Thresholds. There all the voltages can be allowed
to vary a little e.g. 12V is set to vary from 13.2 to 10.8. Same
for CPU core (+1.52V), set to go from 2.325 to 0.725.
There is no variation for the processor fan.
Back tomorrow

 

[JD]

Paul wrote:
JD wrote:
I have a CPU fan that runs all the time at around 4,100 rpm.
This is completely unnecessary when the weather is cool. I believe
a speed
of about 3,000 should be ok at present.

Is there any such program around? I know about SpeedFan but I think
it's a primitive piece of work. The CPU needs a delicate touch.

I did a search and found
http://wareseeker.com/free-cpu-fan-speed-control-software/
However it's hard to tell whether they are discussing the cpu speed
or the fan speed.
Anyone have experience of these?

TIA

Have you looked at your BIOS functions ? Maybe there is
an option in there to control the fan.

Paul

Great suggestion Paul.

I looked in the BIOS and found 2 options for the fan
Fan Control - [Enabled}
Lowest Fan Speed - [Slow]

The first one had no speed control as far as I could see and was the
existing
setting since the motherboard was installed
I set it to the 2nd one and rebooted.
It was exactly the same as before - whizzing along at 4,100 + or - a
few hundred.

I did have this fan plugged into the right socket - it is right
beside the CPU.
I looked in Control Panel - Add-remove hardware and it was no help.
Likewise in the Control Panel itself.
Do you know of any other possible location for a fan speed controller?

TIA

Maybe the next test, is to try Speedfan. If Speedfan cannot get any
response from the fan, then it could mean there simply isn't
a hardware feature there to control the speed with. (It could mean,
for example, that you've mixed incompatible components together.
Or that the motherboard makers are cheapskates.)

The rest of this is some background. Mixing a three pin fan with
a four pin fan header, may deprive you of a control method. And
that is an example of how you can accidentally be stuck with
a screaming fan.

*******

The CPU fan header has a couple features to control fan speed.
Back in the "three pin header" days, voltage control was used.
The fan normally runs from 12V. But the motherboard could control
the voltage, and deliver a variable voltage between 7V and 12V.
This would take a PWM output from the controller, and require a
MOSFET or transistor near the fan header, plus a capacitor,
to convert the pulse width modulated control signal, into
a voltage. It costs the motherboard maker some money to do that.

X <--- RPM (from fan to motherboard, for monitoring)
X ---> 7 to 12V to power fan
X --- Ground

If you're using Speedfan, Speedfan may find the registers that
control the PWM output. The register can be programmed, and
the hardware chip is then outputting a PWM signal. But if the
motherboard maker wants to save money, they don't bother to
install the interface circuit (the MOSFET and capacitor). Speedfan
cannot tell those components are missing. So one of the checks
I make, when someone has this problem, is to look at a picture
of the motherboard, and see if the appropriate looking components
are installed nearby.

(Some general rules of thumb. Prebuilt systems from HP/Dell/Gateway
are the ones most likely to have fan control per header. Which
means they have the most fan control of all. On an Asus motherboard,
the cheapest boards have no fan control. A board with QFan has the
CPU fan controlled. A higher end board with QFan2, has two headers
under control, one via CPU temp, one via chassis temp. So that should
give some idea what to expect in terms of working channels. With the
four pin fan header generation, you're much more likely to have a
CPU fan control, so the situation should be getting slightly better
as time passes.)

*******

The second control method, is of more recent design. Both
Intel and AMD now use four pin fan headers for CPU. The fourth pin
is (what a surprise) PWM. What is happening in this case,
is the responsibility for the MOSFET and capacitor, is now
up to the fan manufacturer, as they're inside the fan. The motherboard
has a fan controller interface on it somewhere (I can't say
right off hand, where this one is located now). The logic
signal output, running at perhaps 25KHz, is delivered on the
fourth wire of the fan. The fan runs at full 12V all the time.
The conversion circuit inside the fan hub, uses the pulse
width of the PWM signal, to control the voltage delivered
to the fan. That means the fan can run at 7V, using a
circuit inside the fan hub to make the 7V from the supplied
12V.

X ---> PWM (from motherboard to fan, 25KHz, indicates speed desired)
X <--- RPM (from fan to motherboard, for monitoring)
X ---> 12V DC (power from motherboard to fan)
X --- Ground

So as a consequence of having that fourth wire and control
method, Intel recommends not attempting to reduce the 12V
fed to such a fan. That recommendation, is so the MOSFET
has sufficient signal applied, so it will be biased properly.

Now, imagine what would happen, if you purchased an aftermarket
heatsink/fan combo, with a three pin connector, and connected
it to a four pin header. No PWM signal. No variable 12V.
And hence, no control method. Again, programs like Speedfan
will feel they're "dialing the knob", but nothing happens.

*******

There is one other feature, which was used in the past with
Intel fans. They had a thermistor in the fan hub. If the
computer case air temperature rises, the fan is set to
spin faster, based on the measurements by the thermistor.
That feature does not lend itself to control by the user.
Its purpose is to compensate for the worse cooling situation
caused by hot case air. So if the computer has poor ventilation,
the CPU fan may scream a lot more than it would in a cooler
running case. Any other control method applied, multiplies
its effect, by the effect provided by the thermistor. So if
the computer case was very cool, the fan may hardly be
turning at all.

Speed = Voltage_controlled_speed * thermistor_set_speed

Anyway, my next steps would be some Speedfan testing, and
some visual inspection. Like, checking whether there is a
three pin fan connected to a four pin header. On an older
motherboard, whether the appropriate components are next
to the three pin headers, and so on. As far as I know, there
isn't a programmatic way of determining whether the controls
are actually hooked up and working. A program could certainly
observe the RPMs, and notice that nothing is happening, but
I'm not aware of any program bothering to carry out such an
analysis for the user.

During the transition from three pin to four pin CPU fan
header, Asus made some motherboards with dual control
methods. The four pin header could be controlled as if
it was a three pin header. There was a BIOS setting,
that determined whether voltage control or PWM
control was used. And that means, on a small range of
motherboards, there is yet another BIOS setting to check
for. That practice was soon discontinued, in favor of
pure PWM control for four pin fan headers. Meaning
that the providers of aftermarket coolers, should
provide proper four pin fans, if they expected
satisfied customers. When you buy a retail CPU now,
from either Intel or AMD, you should expect to
find a four pin fan packaged with the retail CPU.

Paul

Thanks again Paul. I haven't read the above yet. Today I
used the Intel Active Monitor and it has a window called
Set Sensor Thresholds. There all the voltages can be allowed
to vary a little e.g. 12V is set to vary from 13.2 to 10.8. Same
for CPU core (+1.52V), set to go from 2.325 to 0.725.
There is no variation for the processor fan.
Back tomorrow

Just checked my fan and find that there are 3 wires coming
from it - black, red and yellow. According to the Intel manual
there are 3 wires and it indicates that no fan control exists.

The SpeedFan I started up while the Intel monitor was running.
I noticed the green line of the SpeedFan varying in length and,
while I was watching, the CPU core voltage started to flicker in
response. It was responding to the movements of SpeedFan. It
even knocked the core voltage down to zero a few times.
Then I shut SpeedFan down. I'm not sure that it is refined
enough to use with 1.5v products. It also seems that the flickering
problems I had earlier were caused by SpeedFan.

 

[Paul]

Just checked my fan and find that there are 3 wires coming
from it - black, red and yellow. According to the Intel manual
there are 3 wires and it indicates that no fan control exists.

The SpeedFan I started up while the Intel monitor was running.
I noticed the green line of the SpeedFan varying in length and,
while I was watching, the CPU core voltage started to flicker in
response. It was responding to the movements of SpeedFan. It
even knocked the core voltage down to zero a few times.
Then I shut SpeedFan down. I'm not sure that it is refined
enough to use with 1.5v products. It also seems that the flickering
problems I had earlier were caused by SpeedFan.

So are you using a three wire fan on a three pin header ?

What combo of parts have you connected together ?

If you mention the make and model of motherboard, maybe I can
find a picture and see whether there are any components of interest
near the fan headers.

Paul

 

[JD]

So are you using a three wire fan on a three pin header ?

What combo of parts have you connected together ?

If you mention the make and model of motherboard, maybe I can
find a picture and see whether there are any components of interest
near the fan headers.

Paul

Thanks again Paul.

Motherboard: D845GEBV2

Here is the link to the Intel board connectors

http://www.intel.com/support/motherboards/desktop/d845gebv2/sb/cs-020055.htm

 

[Paul]

Thanks again Paul.

Motherboard: D845GEBV2

Here is the link to the Intel board connectors

http://www.intel.com/support/motherboards/desktop/d845gebv2/sb/cs-020055.htm

The documentation refers to a fan control ASIC.

http://downloadmirror.intel.com/15323/eng/D845GERG2_D845GEBV2_TechProdSpec.pdf

The SuperI/O chip appears pretty basic. This one has only two tachometer (RPM)
channels. Apparently, a separate chip is used to provide both fan control, and
the ability to monitor more fans than the two the LPC47M172 supports. And that
ASIC remains unnamed in the above Intel document.

( LPC47M172 )
http://www.smsc.com/index.php?pid=106&tid=249

I found one thread, that mentioned LM85B as a possibility for a separate
fan control.

http://www.national.com/opf/LM/LM85.html

http://www.national.com/images/pf/LM85/20035301.pdf (pretty rich set of functions)

It is a 24 pin chip.

http://www.national.com/ds/LM/LM85.pdf

Chip might look like this.

http://www.national.com/packaging/folders/mqa24.html

Here is a picture of what Speedfan might show, if this chip was on
your board. Apparently it is a manufacturing option. Too bad there
isn't an easy way to determine what options are on board.

http://i214.photobucket.com/albums/cc178/whelderwheels613/Untitled-2.jpg

( http://www.maximumpc.com/forums/viewtopic.php?t=71981 )

If you had both, they're connected via the following busses.

LPC SMBUS (serial, low speed)
| |
| |
LPC47M172 LM85B

The difference between the two busses, is that if you use two
software programs to monitor the SMBUS, you can get some bad
readings in both programs. The SMBUS really needs a software
semaphore, so that only one program accesses the bus interface
at a time. There is no industry wide agreement on that, and
as a result, programs can get corrupted readings if two programs
are at work. LPC should be much better in this regard. I would
not expect corrupted readings over LPC. What happens on SMBUS,
is a second software program, can cause a serial bus transfer
to be aborted while the first software program is waiting for
its data. (The thing using the bus, could be the BIOS.)

In this picture, you can see that both chips are present.
The first "Fan1,Fan2" is coming from LPC47M172. The second
"Fan1,Fan2,Fan3,Fan4" comes from the LM85B. It is anyone's
guess as to how the three fan headers are connected to those
six interfaces.

http://i214.photobucket.com/albums/cc178/whelderwheels613/untitled-1.jpg

So your board is more complicated than the average board. All the
motherboards I have here, have only one chip.

Perhaps a picture of your board ?

http://imgk-a.dena.ne.jp/exk5/20090326/216/128345580_1.jpg

In that picture, I can't positively identify the LM85B. It might
be up near the top of the picture, to the left of the DIMM sockets.
I don't see anything near the fan headers, to do the PWM conversion.
The LM85B only has 8ma drive on its open drain PWM control
signals, so that isn't enough to drive a fan directly.
So there has to be something else to do it.

My guess at this point would be, if you see the weird
"Fan1,Fan2" "Fan1,Fan2,Fan3,Fan4" in Speedfan, then assume
the LM85B is present. And it wouldn't make sense to install
the LM85B without also installing any fan header interfacing
components. So if the LM85B shows up, you should be able
to adjust a fan and hear the speed change.

If all you see is "Fan1,Fan2", then you've got the LPC47M172,
which only monitors two fans and doesn't attempt to control
them. All the control functions would be in the LM85B.

My best guess,
Paul

 

[JD]

The documentation refers to a fan control ASIC.

http://downloadmirror.intel.com/15323/eng/D845GERG2_D845GEBV2_TechProdSpec.pdf


The SuperI/O chip appears pretty basic. This one has only two tachometer
(RPM)
channels. Apparently, a separate chip is used to provide both fan
control, and
the ability to monitor more fans than the two the LPC47M172 supports.
And that
ASIC remains unnamed in the above Intel document.

( LPC47M172 )
http://www.smsc.com/index.php?pid=106&tid=249

I found one thread, that mentioned LM85B as a possibility for a separate
fan control.

http://www.national.com/opf/LM/LM85.html

http://www.national.com/images/pf/LM85/20035301.pdf (pretty rich set of
functions)

It is a 24 pin chip.

http://www.national.com/ds/LM/LM85.pdf

Chip might look like this.

http://www.national.com/packaging/folders/mqa24.html

Here is a picture of what Speedfan might show, if this chip was on
your board. Apparently it is a manufacturing option. Too bad there
isn't an easy way to determine what options are on board.

http://i214.photobucket.com/albums/cc178/whelderwheels613/Untitled-2.jpg

( http://www.maximumpc.com/forums/viewtopic.php?t=71981 )

If you had both, they're connected via the following busses.

LPC SMBUS (serial, low speed)
| |
| |
LPC47M172 LM85B

The difference between the two busses, is that if you use two
software programs to monitor the SMBUS, you can get some bad
readings in both programs. The SMBUS really needs a software
semaphore, so that only one program accesses the bus interface
at a time. There is no industry wide agreement on that, and
as a result, programs can get corrupted readings if two programs
are at work. LPC should be much better in this regard. I would
not expect corrupted readings over LPC. What happens on SMBUS,
is a second software program, can cause a serial bus transfer
to be aborted while the first software program is waiting for
its data. (The thing using the bus, could be the BIOS.)

In this picture, you can see that both chips are present.
The first "Fan1,Fan2" is coming from LPC47M172. The second
"Fan1,Fan2,Fan3,Fan4" comes from the LM85B. It is anyone's
guess as to how the three fan headers are connected to those
six interfaces.

http://i214.photobucket.com/albums/cc178/whelderwheels613/untitled-1.jpg

So your board is more complicated than the average board. All the
motherboards I have here, have only one chip.

Perhaps a picture of your board ?

http://imgk-a.dena.ne.jp/exk5/20090326/216/128345580_1.jpg

In that picture, I can't positively identify the LM85B. It might
be up near the top of the picture, to the left of the DIMM sockets.
I don't see anything near the fan headers, to do the PWM conversion.
The LM85B only has 8ma drive on its open drain PWM control
signals, so that isn't enough to drive a fan directly.
So there has to be something else to do it.

My guess at this point would be, if you see the weird
"Fan1,Fan2" "Fan1,Fan2,Fan3,Fan4" in Speedfan, then assume
the LM85B is present. And it wouldn't make sense to install
the LM85B without also installing any fan header interfacing
components. So if the LM85B shows up, you should be able
to adjust a fan and hear the speed change.

If all you see is "Fan1,Fan2", then you've got the LPC47M172,
which only monitors two fans and doesn't attempt to control
them. All the control functions would be in the LM85B.

My best guess,
Paul

Many thanks again Paul. You are a huge help.

Yesterday I spent an hour online looking for a good quality picture of
the motherboard and failed, even on the Intel web site. The images were
far too small to see any writing on the board. Of course I never even
dreamed
of visiting Japan to look for it ;-) You are a resourceful guy! Were you
thinking of a geisha girl when you visited?

Then I opened up the computer and had a closer look. The case fan (only
one)
is connected to the power supply and not to the board. I looked around for
other connections and there were no more than appeared on the schematic we
looked at a few days ago. I'll change that case fan connection to the
motherboard when I get a plug for the connection and some time.

I also looked in the area to the rear of the CPU between the AGP card
and the
power supply. There is the 12V board supply connector and two other small
connectors beside the AGP card. These are for ATAPI and the rear case fan
- not installed.

I started up Speedfan and it does indeed show 4 fans. In the few minutes
it was
running it knocked the CPU-core voltage reading down to zero 3 times and
each time
the Intel monitor popped up a warning. That SpeedFan prog makes me worry.

The CPU fan has been running and whining at about 4,300 rpm while all
the temperatures
are showing 25 C. Dumb design this system.

I'm still trying to get through all your post above. Back soon, I hope.
Thanks again for
your efforts.

 

[Paul]

Many thanks again Paul. You are a huge help.

Yesterday I spent an hour online looking for a good quality picture of
the motherboard and failed, even on the Intel web site. The images were
far too small to see any writing on the board. Of course I never even
dreamed
of visiting Japan to look for it ;-) You are a resourceful guy! Were you
thinking of a geisha girl when you visited?

Then I opened up the computer and had a closer look. The case fan (only
one)
is connected to the power supply and not to the board. I looked around for
other connections and there were no more than appeared on the schematic we
looked at a few days ago. I'll change that case fan connection to the
motherboard when I get a plug for the connection and some time.

I also looked in the area to the rear of the CPU between the AGP card
and the
power supply. There is the 12V board supply connector and two other small
connectors beside the AGP card. These are for ATAPI and the rear case fan
- not installed.

I started up Speedfan and it does indeed show 4 fans. In the few minutes
it was
running it knocked the CPU-core voltage reading down to zero 3 times and
each time
the Intel monitor popped up a warning. That SpeedFan prog makes me worry.

The CPU fan has been running and whining at about 4,300 rpm while all
the temperatures
are showing 25 C. Dumb design this system.

I'm still trying to get through all your post above. Back soon, I hope.
Thanks again for
your efforts.

If you have readings getting corrupted, they're probably coming from
the LM85B, which sits on the SMBUS. It means there is a second piece
of software accessing the chip and monitoring it. That could be the
"Intel monitor". If one program runs at a time, and you exit the other
program, you may find the readings more reliable. If the people
writing the code for those programs could agree on an access method
to the hardware, there might never have been any corruption in
the first place. Since nobody in a leadership role, could define
a semaphore for access to SMBUS, we're stuck with getting crappy
readings. The only time the SMBUS is guaranteed reliable, is
when the BIOS is doing its POST routine.

In terms of connections then, you're saying the case cooling fan is
connected to a 4 pin Molex power connector from the power supply ? Or is
there a fan header cable coming from the supply, with the smaller (motherboard
style) connector on it ? Some power supplies have a voltage controlled two
or three pin fan connector, and the voltage is set according to how hot
the power supply is getting. Since the power supply gets a stream of
air from the computer case, the mechanism roughly causes the case fan
to speed up, when the computer case air is getting hot.

I presume the CPU cooler is plugged into the CPU header on the motherboard.

If you're seeing evidence of the LM85B in Speedfan, then you should be
able to make changes to its registers. If a BIOS or other software is
also present and making changes, there is nothing to prevent the two programs
or softwares from getting into a fight. I've had pretty good luck here,
because my BIOSes tend to set the hardware just the once, and then they
don't do any more writes. It allows the usage of Speedfan, without problems.

You might wonder how the BIOS can run, while the operating system is
present. There is something called SMM, which is a means by which the
BIOS can take control from the OS, for short intervals. If implemented
poorly, this can result in detectable issues at the OS level. If the
outage caused by the BIOS is long enough, you can lose the counting of
clock ticks (causing system time to drift while the OS is running).
If the outage is a shorter interval, the system time may remain accurate,
but the DPC latency (time until a deferred procedure call is serviced)
may be lengthened. There is one utility for checking that, a
DPC Latency utility, that can be used to check. For example, on
my newest system, the average is perhaps 800 microseconds for
DPCs to be serviced. I may see the occasional millisecond level
response, if the system is heavily loaded. So if SMM steals
control of the system for a long period of time, the only
evidence might be collected indirectly, by measuring DPC
latency.

http://en.wikipedia.org/wiki/System_Management_Mode

I've never seen any product documentation for motherboards, that
references SMM or what the manufacturer may be doing or not doing.
So whether there is any usage of SMM, is any one's guess. But if
your SMBUS was getting corrupted, and you were absolutely sure
that only Speedfan was running, it would suggest the BIOS
is popping in occasionally, and doing something to the SMBUS.

Paul

 

[JD]

If you have readings getting corrupted, they're probably coming from
the LM85B, which sits on the SMBUS. It means there is a second piece
of software accessing the chip and monitoring it. That could be the
"Intel monitor". If one program runs at a time, and you exit the other
program, you may find the readings more reliable. If the people
writing the code for those programs could agree on an access method
to the hardware, there might never have been any corruption in
the first place. Since nobody in a leadership role, could define
a semaphore for access to SMBUS, we're stuck with getting crappy
readings. The only time the SMBUS is guaranteed reliable, is
when the BIOS is doing its POST routine.

If you are sure of the that SpeedFan won't damage the system, I'll use
it and leave Intel's program off for the present.

In terms of connections then, you're saying the case cooling fan is
connected to a 4 pin Molex power connector from the power supply ?

This is correct - it is connected directly to the computer's power supply.

Or is

there a fan header cable coming from the supply, with the smaller
(motherboard
style) connector on it ? Some power supplies have a voltage controlled two
or three pin fan connector, and the voltage is set according to how hot
the power supply is getting. Since the power supply gets a stream of
air from the computer case, the mechanism roughly causes the case fan
to speed up, when the computer case air is getting hot.

I presume the CPU cooler is plugged into the CPU header on the motherboard.

Yes, it is.

If you're seeing evidence of the LM85B in Speedfan, then you should be
able to make changes to its registers. If a BIOS or other software is
also present and making changes, there is nothing to prevent the two
programs or softwares from getting into a fight. I've had pretty good luck here,
because my BIOSes tend to set the hardware just the once, and then they
don't do any more writes. It allows the usage of Speedfan, without
problems.

You might wonder how the BIOS can run, while the operating system is
present. There is something called SMM, which is a means by which the
BIOS can take control from the OS, for short intervals. If implemented
poorly, this can result in detectable issues at the OS level. If the
outage caused by the BIOS is long enough, you can lose the counting of
clock ticks (causing system time to drift while the OS is running).
If the outage is a shorter interval, the system time may remain accurate,
but the DPC latency (time until a deferred procedure call is serviced)
may be lengthened. There is one utility for checking that, a
DPC Latency utility, that can be used to check. For example, on
my newest system, the average is perhaps 800 microseconds for
DPCs to be serviced. I may see the occasional millisecond level
response, if the system is heavily loaded. So if SMM steals
control of the system for a long period of time, the only
evidence might be collected indirectly, by measuring DPC
latency.

http://en.wikipedia.org/wiki/System_Management_Mode

I've never seen any product documentation for motherboards, that
references SMM or what the manufacturer may be doing or not doing.
So whether there is any usage of SMM, is any one's guess. But if
your SMBUS was getting corrupted, and you were absolutely sure
that only Speedfan was running, it would suggest the BIOS
is popping in occasionally, and doing something to the SMBUS.

OK, so I'll leave Intel's prog out for now and what do you suggest that I
do with SpeedFan and, if necessary, the BIOS?

Paul

Thanks again.

 

[Paul]

I forgot to mention that the case fan is connected to the power supply
and has only 2 wires and is probably not compatible with the board
connection.
I guess I should look for a 3 wire fan of the same size and connect it
to the
motherboard..

You can connect the two wire case fan to the fan header. It would still
get power. The only issue with a connection to the motherboard header,
is if the fan draws a lot of current. There are a few pre-built
computers, where a fan drawing one ampere is used, and that is
too much for a regular fan header. The motherboard manual sometimes
tells us the current flow limitations of a header, and so that is
something to keep in mind. If the case cooling fan draws somewhere
between 12V @ 100mA and 12V @ 350mA, that might be safe to connect
to the header.

Check what is printed on the hub of the fan. The label sometimes
includes power in watts or current in milliamps, from which you
can decide whether the fan really should stay connected
directly to the power supply.

I have one large fan here, on another computer, and it draws close
to 1000mA (1 amp). I have it connected directly to the power supply.
I don't think the motherboard on that computer, could handle it.

A 2 wire fan cannot be monitored for RPMs (at least the normal way
via an RPM signal). But you could still vary the voltage to the
fan, if the motherboard has control capabilities on that particular
fan header.

Paul

 

[JD]

If you are sure of the that SpeedFan won't damage the system, I'll use
it and leave Intel's program off for the present.

This is correct - it is connected directly to the computer's power supply.

Or is

Yes, it is.


OK, so I'll leave Intel's prog out for now and what do you suggest that I
do with SpeedFan and, if necessary, the BIOS?


Thanks again.

I forgot to mention that the case fan is connected to the power
supply
and has only 2 wires and is probably not compatible with the
board connection.
I guess I should look for a 3 wire fan of the same size and
connect it to the
motherboard..

 

[JD]

You can connect the two wire case fan to the fan header. It would still
get power. The only issue with a connection to the motherboard header,
is if the fan draws a lot of current. There are a few pre-built
computers, where a fan drawing one ampere is used, and that is
too much for a regular fan header. The motherboard manual sometimes
tells us the current flow limitations of a header, and so that is
something to keep in mind. If the case cooling fan draws somewhere
between 12V @ 100mA and 12V @ 350mA, that might be safe to connect
to the header.

Is this oddball name "fan header" the fan connection point to the
motherboard?

Check what is printed on the hub of the fan. The label sometimes
includes power in watts or current in milliamps, from which you
can decide whether the fan really should stay connected
directly to the power supply.

Yes, I think I'm in luck. The rating is 12v, 0.15A.

I have one large fan here, on another computer, and it draws close
to 1000mA (1 amp). I have it connected directly to the power supply.
I don't think the motherboard on that computer, could handle it.

Phew!That's quite a fan.

A 2 wire fan cannot be monitored for RPMs (at least the normal way
via an RPM signal). But you could still vary the voltage to the
fan, if the motherboard has control capabilities on that particular
fan header.

I'll look for a connector for that fan.

Paul

Thanks again

 

[JD]

Is this oddball name "fan header" the fan connection point to the
motherboard?


Yes, I think I'm in luck. The rating is 12v, 0.15A.


Phew!That's quite a fan.


I'll look for a connector for that fan.


Thanks again

It appears that SpeedFan does NOT work with my motherboard. Speed
changes can be attempted on SpeedFan but they do nothing and my CPU
fan is still running at about 4,300 rpm. The BIOS has a variable
setting
for the fan or fans but it seems to be dead too.