What's the PWR_FAN header for?

On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
I've assumed that it's the proper place to connect the three-pin fan
header plug from my PSU (Antec TruePower II). I don't think the
manual says anything more about it than to label it.
Clearly, it would NOT be there to provide power to that particular
fan, so I deduce that it's there to provide rpm monitoring for the PSU
fan.

But the only fan speeds I can find reported are the CPU and the
CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
nVidia Monitor. What am I missing or misunderstanding here?

Thanks,

Ron

On Fri, 29 Jul 2005 01:39:32 GMT, milleron
<> wrote:

>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>I've assumed that it's the proper place to connect the three-pin fan
>header plug from my PSU (Antec TruePower II). I don't think the
>manual says anything more about it than to label it.
>Clearly, it would NOT be there to provide power to that particular
>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>fan.
>
>But the only fan speeds I can find reported are the CPU and the
>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>nVidia Monitor. What am I missing or misunderstanding here?
>
>Thanks,
>
>Ron

See 2-24 of the manual (PDF), it's just another fan header.

thats correct. no voltage, just a psu rpm monitor...

On Fri, 29 Jul 2005 01:39:32 GMT, milleron
<> wrote:

>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>I've assumed that it's the proper place to connect the three-pin fan
>header plug from my PSU (Antec TruePower II). I don't think the
>manual says anything more about it than to label it.
>Clearly, it would NOT be there to provide power to that particular
>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>fan.
>
>But the only fan speeds I can find reported are the CPU and the
>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>nVidia Monitor. What am I missing or misunderstanding here?
>
>Thanks,
>
>Ron

In article <>,
wrote:

> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
> I've assumed that it's the proper place to connect the three-pin fan
> header plug from my PSU (Antec TruePower II). I don't think the
> manual says anything more about it than to label it.
> Clearly, it would NOT be there to provide power to that particular
> fan, so I deduce that it's there to provide rpm monitoring for the PSU
> fan.
>
> But the only fan speeds I can find reported are the CPU and the
> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
> nVidia Monitor. What am I missing or misunderstanding here?
>
> Thanks,
>
> Ron

The Premium manual lists CPU, CHA1, CHIP as the three fan
speed monitoring channels. It would seem they ran out of
channels, and considered the CHIP header to be more important
than the PSU header. Now, normally, there would be no need
to put +12V on that header, but perhaps +12V and GND are the
only connections.

Assuming your board has an ITE IT8712 hardware monitor chip,
there are actually five fan control channels and five fan
monitoring channels. If the motherboard has a GAME/MIDI header,
two pins from the fan control group and two pins from the
fan monitoring group, are hijacked to make joystick interface
pins. That leaves three channels of fan control and three
channels of RPM monitoring. Seeing as the manual lists
CPU, CHA1, CHIP as the monitor headers, any other headers
are at best just power plugs for fans. You could check to see
if they have power, by plugging in a fan (with the power off!).

Paul

On Fri, 29 Jul 2005 01:47:16 -0400, (Paul) wrote:

>In article <>,
> wrote:
>
>> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>> I've assumed that it's the proper place to connect the three-pin fan
>> header plug from my PSU (Antec TruePower II). I don't think the
>> manual says anything more about it than to label it.
>> Clearly, it would NOT be there to provide power to that particular
>> fan, so I deduce that it's there to provide rpm monitoring for the PSU
>> fan.
>>
>> But the only fan speeds I can find reported are the CPU and the
>> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>> nVidia Monitor. What am I missing or misunderstanding here?
>>
>> Thanks,
>>
>> Ron
>
>The Premium manual lists CPU, CHA1, CHIP as the three fan
>speed monitoring channels. It would seem they ran out of
>channels, and considered the CHIP header to be more important
>than the PSU header. Now, normally, there would be no need
>to put +12V on that header, but perhaps +12V and GND are the
>only connections.
>
>Assuming your board has an ITE IT8712 hardware monitor chip,
>there are actually five fan control channels and five fan
>monitoring channels. If the motherboard has a GAME/MIDI header,
>two pins from the fan control group and two pins from the
>fan monitoring group, are hijacked to make joystick interface
>pins. That leaves three channels of fan control and three
>channels of RPM monitoring. Seeing as the manual lists
>CPU, CHA1, CHIP as the monitor headers, any other headers
>are at best just power plugs for fans. You could check to see
>if they have power, by plugging in a fan (with the power off!).
>
> Paul

Thanks, Paul. So it looks as though the header marked "PWR_FAN" is,
in reality, for any fan OTHER THAN the "PWR FAN" because all the PSU
fan requires is rpm monitoring, but the only thing that header
actually provides is power. Asus was really stupid on this one, then.

Ron

On Thu, 28 Jul 2005 22:36:56 -0500, Ed <> wrote:

>On Fri, 29 Jul 2005 01:39:32 GMT, milleron
><> wrote:
>
>>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>I've assumed that it's the proper place to connect the three-pin fan
>>header plug from my PSU (Antec TruePower II). I don't think the
>>manual says anything more about it than to label it.
>>Clearly, it would NOT be there to provide power to that particular
>>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>fan.
>>
>>But the only fan speeds I can find reported are the CPU and the
>>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>nVidia Monitor. What am I missing or misunderstanding here?
>>
>>Thanks,
>>
>>Ron
>
>See 2-24 of the manual (PDF), it's just another fan header.

Thanks for the reply, but I did read the manual before posting.
Although the PWR_FAN header is pictured there on 2-24, it certainly
does not state that it's "just another fan header" and definitely does
not say anything about its rpm-monitoring capability. In fact, it
gives no information about it (other than that it's not governed by
Q-Fan), which is why I posted the question here.



Ron

On Fri, 29 Jul 2005 04:19:58 GMT, timmy <> wrote:

>thats correct. no voltage, just a psu rpm monitor...

If it's an rpm monitor, where is the rpm result reported?????

>
>On Fri, 29 Jul 2005 01:39:32 GMT, milleron
><> wrote:
>
>>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>I've assumed that it's the proper place to connect the three-pin fan
>>header plug from my PSU (Antec TruePower II). I don't think the
>>manual says anything more about it than to label it.
>>Clearly, it would NOT be there to provide power to that particular
>>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>fan.
>>
>>But the only fan speeds I can find reported are the CPU and the
>>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>nVidia Monitor. What am I missing or misunderstanding here?
>>
>>Thanks,
>>
>>Ron

Ron

Some power supplies have a separate lead that can be plugged into the Fan
Header on the motherboard. The motherboard will then controll the power
supply fan or it will just monitor the speed of the fan.


"milleron" <> wrote in message
news:...
> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
> I've assumed that it's the proper place to connect the three-pin fan
> header plug from my PSU (Antec TruePower II). I don't think the
> manual says anything more about it than to label it.
> Clearly, it would NOT be there to provide power to that particular
> fan, so I deduce that it's there to provide rpm monitoring for the PSU
> fan.
>
> But the only fan speeds I can find reported are the CPU and the
> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
> nVidia Monitor. What am I missing or misunderstanding here?
>
> Thanks,
>
> Ron

"RonK" <> wrote in message
news:tZwGe.6718$. ..
> Some power supplies have a separate lead that can be plugged into the Fan
> Header on the motherboard. The motherboard will then controll the power
> supply fan or it will just monitor the speed of the fan.
>

Yes, my Antec NeoPower 480 has a 3-pin fan sensor on it.
The trouble is that the A8N-SLI Deluxe does not give you the ability to read
the RPM anywhere.
There is nothing in the BIOS, Asus Probe does not show the reading either.
So far I have tried:

Sandra
Speed Fan
MBM5
Everest

And not one of them is able to read the information form the header.

On the P4C800 the header reads the power supply fan fine, if you have a
supply with the lead. It outputs it to the Asus Probe program. Funny they
wouldn't do that on your board as well.
"milleron" <> wrote in message
news:...
> On Fri, 29 Jul 2005 01:47:16 -0400, (Paul) wrote:
>
>>In article <>,
>> wrote:
>>
>>> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>> I've assumed that it's the proper place to connect the three-pin fan
>>> header plug from my PSU (Antec TruePower II). I don't think the
>>> manual says anything more about it than to label it.
>>> Clearly, it would NOT be there to provide power to that particular
>>> fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>> fan.
>>>
>>> But the only fan speeds I can find reported are the CPU and the
>>> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>> nVidia Monitor. What am I missing or misunderstanding here?
>>>
>>> Thanks,
>>>
>>> Ron
>>
>>The Premium manual lists CPU, CHA1, CHIP as the three fan
>>speed monitoring channels. It would seem they ran out of
>>channels, and considered the CHIP header to be more important
>>than the PSU header. Now, normally, there would be no need
>>to put +12V on that header, but perhaps +12V and GND are the
>>only connections.
>>
>>Assuming your board has an ITE IT8712 hardware monitor chip,
>>there are actually five fan control channels and five fan
>>monitoring channels. If the motherboard has a GAME/MIDI header,
>>two pins from the fan control group and two pins from the
>>fan monitoring group, are hijacked to make joystick interface
>>pins. That leaves three channels of fan control and three
>>channels of RPM monitoring. Seeing as the manual lists
>>CPU, CHA1, CHIP as the monitor headers, any other headers
>>are at best just power plugs for fans. You could check to see
>>if they have power, by plugging in a fan (with the power off!).
>>
>> Paul
>
> Thanks, Paul. So it looks as though the header marked "PWR_FAN" is,
> in reality, for any fan OTHER THAN the "PWR FAN" because all the PSU
> fan requires is rpm monitoring, but the only thing that header
> actually provides is power. Asus was really stupid on this one, then.
>
> Ron