CPU fan speed report inconsistent

I'm running an Asus A8N-SLI motherboard, and just rebooted for the
first time in several months. I received at the beginning of the boot
the message: Warning: Your Computer CHIP fan fail or speed too low.

But when I enter the Phoenix BIOS setup, I see the following:

CPU Temperature 37ø C
M/B Temperature 36ø C
CPU FAN Speed 3125 RPM
CPU Target Temperature 72ø
CPU Fan Speed Warning [1200 RPM]

So, according to the BIOS, everying is nominal. What could explain the
initial alert?
--

Haines Brown
KB1GRM

On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
<> wrote:

>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>first time in several months. I received at the beginning of the boot
>the message: Warning: Your Computer CHIP fan fail or speed too low.
>
>But when I enter the Phoenix BIOS setup, I see the following:
>
> CPU Temperature 37ø C
> M/B Temperature 36ø C
> CPU FAN Speed 3125 RPM
> CPU Target Temperature 72ø
> CPU Fan Speed Warning [1200 RPM]
>
>So, according to the BIOS, everying is nominal. What could explain the
>initial alert?

Fan slow to start. Reboot and see if it happens again. If it doesn't
shut the thing down for several hours and let it get to room
temperature and try again. If you get the warning replace the fan.

On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
<> wrote:

>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>first time in several months. I received at the beginning of the boot
>the message: Warning: Your Computer CHIP fan fail or speed too low.
>
>But when I enter the Phoenix BIOS setup, I see the following:
>
> CPU Temperature 37ø C
> M/B Temperature 36ø C
> CPU FAN Speed 3125 RPM
> CPU Target Temperature 72ø
> CPU Fan Speed Warning [1200 RPM]
>
>So, according to the BIOS, everying is nominal. What could explain the
>initial alert?

I've just replaced a fan that was showing a large drop in speed every
minute or two. You can't trust a bios snapshot. Monitor the speed for
a few minutes to see if it is changing.

--
Steve Wolstenholme Neural Planner Software

EasyNN-plus. The easy way to build neural networks.
http://www.easynn.com

Chris Hill <> writes:

> On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
> <> wrote:
>
>>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>>first time in several months. I received at the beginning of the boot
>>the message: Warning: Your Computer CHIP fan fail or speed too low.
>>
>>But when I enter the Phoenix BIOS setup, I see the following:
>>
>> CPU Temperature 37x C
>> M/B Temperature 36x C
>> CPU FAN Speed 3125 RPM
>> CPU Target Temperature 72x
>> CPU Fan Speed Warning [1200 RPM]
>>
>>So, according to the BIOS, everying is nominal. What could explain the
>>initial alert?
>
> Fan slow to start. Reboot and see if it happens again. If it doesn't
> shut the thing down for several hours and let it get to room
> temperature and try again. If you get the warning replace the fan.

Thanks: that didn't occur to me. A slow start would certainly spell
trouble.

I rebooted three times and the problem repeated itself. Looks like
I'll have to change the fan. Hope I don't have to replace the heat
sink with it.


--

Haines Brown
KB1GRM

,uk writes:

> On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
> <> wrote:
>
>>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>>first time in several months. I received at the beginning of the boot
>>the message: Warning: Your Computer CHIP fan fail or speed too low.

> minute or two. You can't trust a bios snapshot. Monitor the speed for
> a few minutes to see if it is changing.

I realize the BIOS monitor is not very reliable, but I have nothing
else to go on. The RPM does vary a very little in time (1% ?). That
suggests the fan is working normally, but I don't see how that bears
on the issue of a slow start up. A slow startup suggests a certain
stickyness at low RPM, which might not affect the speed at high RPM. I
assume that if there is such a low RPM stickyness that it might well
suggest that one day it will fail to start spinning altogether. If the
CPU gets too hot, I vaguely recall an audible alarm, but I'm not sure
at this point. It sure would be nice insurance while I'm deciding on
whether to replace the fan.
--

Haines Brown
KB1GRM

Previously Haines Brown <> wrote:
> ,uk writes:

>> On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
>> <> wrote:
>>
>>>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>>>first time in several months. I received at the beginning of the boot
>>>the message: Warning: Your Computer CHIP fan fail or speed too low.

>> minute or two. You can't trust a bios snapshot. Monitor the speed for
>> a few minutes to see if it is changing.

> I realize the BIOS monitor is not very reliable, but I have nothing
> else to go on. The RPM does vary a very little in time (1% ?). That
> suggests the fan is working normally, but I don't see how that bears
> on the issue of a slow start up. A slow startup suggests a certain
> stickyness at low RPM, which might not affect the speed at high RPM. I
> assume that if there is such a low RPM stickyness that it might well
> suggest that one day it will fail to start spinning altogether. If the
> CPU gets too hot, I vaguely recall an audible alarm, but I'm not sure
> at this point. It sure would be nice insurance while I'm deciding on
> whether to replace the fan.

Maybe some additional info: The RPM monitor has a very coarse
resolution (likely the 1% variation you see) and does not
work outside a specific RPM-range. It has a pre-divider that
needs to be set right for the relevant RPM-Range. It is possible
thet you fan is just, say, 20% slower on startup, maybe because
the bnearings need to get warm or whatever and that this falls
out of the measurable RPM range for the set pre-divider. The same
effect could happen if it just need a little longer to reach full
speed (if it is a low-quality fan, e.g. YS-tech, without fan
controller and heavy rotor complete spin-up can take a while)
than it takes the monitor-chip to make its first measurement.

You may be able to test this by monitring the RPM numbers and slowing
down the fan a little with your finger (applied in the center of the
fan).

Arno

Haines Brown wrote:

> Chris Hill <> writes:
>>On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
>><> wrote:
>>
>>>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>>>first time in several months. I received at the beginning of the boot
>>>the message: Warning: Your Computer CHIP fan fail or speed too low.
>>>
>>>But when I enter the Phoenix BIOS setup, I see the following:
>>>
>>> CPU Temperature 37x C
>>> M/B Temperature 36x C
>>> CPU FAN Speed 3125 RPM
>>> CPU Target Temperature 72x
>>> CPU Fan Speed Warning [1200 RPM]
>>>
>>>So, according to the BIOS, everying is nominal. What could explain the
>>>initial alert?
>>
>>Fan slow to start. Reboot and see if it happens again. If it doesn't
>>shut the thing down for several hours and let it get to room
>>temperature and try again. If you get the warning replace the fan.
>
> Thanks: that didn't occur to me. A slow start would certainly spell
> trouble.
>
> I rebooted three times and the problem repeated itself. Looks like
> I'll have to change the fan. Hope I don't have to replace the heat
> sink with it.

IMHO there's no reason why you should have to replace the heat sink.
Depending on how the fan's mounted you may not even have to remove
the heat sink from the board and processor. While the fan's off use
a little canned air to blow the stuff off the heat sink, and while
the cover's off vacuum out the corners of the case as well.

--
-- Marten Kemp
(Fix name and ISP to reply)
-=-=-
.... The only thing not wasted on the stupid is a bullet,
and even that might depend on how many bullets you have
and how many you might need.
-M.F.S. on alt.support.childfree 5/03
* TagZilla 0.059 * http://tagzilla.mozdev.org

Haines Brown wrote:

> ,uk writes:
>
>
>>On Tue, 20 Dec 2005 12:39:22 GMT, Haines Brown
>><> wrote:
>>
>>
>>>I'm running an Asus A8N-SLI motherboard, and just rebooted for the
>>>first time in several months. I received at the beginning of the boot
>>>the message: Warning: Your Computer CHIP fan fail or speed too low.
>
>>minute or two. You can't trust a bios snapshot. Monitor the speed for
>>a few minutes to see if it is changing.
>
> I realize the BIOS monitor is not very reliable, but I have nothing
> else to go on. The RPM does vary a very little in time (1% ?). That
> suggests the fan is working normally, but I don't see how that bears
> on the issue of a slow start up. A slow startup suggests a certain
> stickyness at low RPM, which might not affect the speed at high RPM. I
> assume that if there is such a low RPM stickyness that it might well
> suggest that one day it will fail to start spinning altogether. If the
> CPU gets too hot, I vaguely recall an audible alarm, but I'm not sure
> at this point. It sure would be nice insurance while I'm deciding on
> whether to replace the fan.

Replace the fan. From the Asus site, the A8N-SLI is for a pretty
fancy CPU. A fan's gotta be a lot less expensive than a new CPU.
I'm not sure that the audible alarm will go off before the CPU's
damaged.

In the meantime, try this: peel the sticker over the center of the
fan back to expose the end of the shaft and use a toothpick to put
a *small* drop of something like 3-in-1 oil on the fan shaft.
_Put the sticker back on_ to keep the oil from getting out and
mucking up things.

--
-- Marten Kemp
(Fix name and ISP to reply)
-=-=-
.... "The more corrupt the society, the more numerous the laws." -- Seneca
"And the more capriciously they get enforced." -- Jack C Lipton
* TagZilla 0.059 * http://tagzilla.mozdev.org

Marten,

Thanks for the suggestion to oil the fan. If that has no effect, I'll
proceed to replace it.

--

Haines Brown
KB1GRM

Haines Brown wrote:

> Marten,
>
> Thanks for the suggestion to oil the fan. If that has no effect, I'll
> proceed to replace it.

You're welcome. I just found out that some fans
don't have the lube hole when I attempted this
on a noisy power supply.

--
-- Marten Kemp
(Fix name and ISP to reply)
-=-=-
.... A man has to live with himself, and he should
see to it that he always has good company.
-Charles Evans Hughes, jurist (1862-1948)
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