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From: Roy on 5 Jun 2010 02:48
Hello group
First I have to admit that I an not a normal user of a desktop as I
am kinda of a laptop guy...<grin>
Due to this I am not really very familiar with desktop hardware
peculiarities that is I why ....
I would like to know if this is normal for a desktop where the fan
seems to run in high gear during start up creating an annoying loud
humming sound?
But when that
desktop is already fully booted up the sound just decreases to a a
nearly silent or very mild hum...

I would be pleased to hear your comments .....

TIA

Roy
From: Paul on 5 Jun 2010 04:30
Roy wrote:
> Hello group
> First I have to admit that I an not a normal user of a desktop as I
> am kinda of a laptop guy...<grin>
> Due to this I am not really very familiar with desktop hardware
> peculiarities that is I why ....
> I would like to know if this is normal for a desktop where the fan
> seems to run in high gear during start up creating an annoying loud
> humming sound?
> But when that
> desktop is already fully booted up the sound just decreases to a a
> nearly silent or very mild hum...
>
> I would be pleased to hear your comments .....
>
> TIA
>
> Roy

OK, the design concept is:

1) The fan is very powerful. It's like they've borrowed the
cooling fan, from a vacuum cleaner. Some of these fans are
rated for more than 100CFM, which is, quite frankly,
ridiculous.

2) The fan has speed control capabilities. A chip, likely the
hardware monitor, has all the control features needed.

3) If no software talks to the fan speed controller, it is
designed to run 100% speed.

4) If the BIOS has any "Automatic Fan Speed" control options,
it is possible for the fan to wind down a few seconds after
power up. The BIOS code is the earliest code to run in the
computer. Some fan speed controllers are autonomous, and the
hardware monitor chip can automatically ramp the fan up and down,
in response to a temperature measurement it is making. But none
of that works, until the hardware monitor chip fan controller
is programmed. The initial reset state of the hardware monitor
chip, is to not control anything. And then the fan runs 100%.

5) A company can write fan control code for the OS level, and run it
from there. It might take two minutes of listening to that awful
noise, until an OS level module, program, or service, runs to fix it.

It's really a bizarre and stupid idea! Engineers can actually
do better than that, but this stupid idea is really cheap.

So you know there is a hardware capability, and it doesn't work
until it is programmed. If it can be programmed by BIOS code (check
the BIOS setup screens), then you may be able to stop the noise
early. If the only control is via code running when the OS is booted,
you may have a longer wait.

*******

To give an example of how I dealt with this:

I bought a new video card. It has the same, stupid cooling fan design.
If no software module comes along and programs the video card fan
controller, the thing howls.

Now, there is no problem in Windows, because the Windows video driver
for the card, knows how to program the fan. After two minutes, there
is "peace in the valley".

But if I boot Linux, the fan howls for the entire Linux session!
Scumbags! Unacceptable!

So what I did was:

1) Disconnect the video card fan from the video card onboard connector.
2) Use a Molex disk drive cable as a source of 12V.
3) Design a voltage reducer, to run the fan from 7 or 8 volts,
instead of the entire 12 volts.

Now, the fan always runs at 20%. I've determined by experiment,
that this provides just as much cooling as the automated fan
control does. But the difference is, the fan can no longer
run 100% speed. It runs at a constant slow speed all the time.
Linux or Windows, it doesn't matter. Now, I don't even think
about that video card any more, because it makes the same
low level noise at all times.

If this is a Dell, some of them use a custom fan connector, where
the pins are not necessarily documented. It makes it more difficult
to hack the kind of solution that I used for my video card.

At this point, all I can suggest is checking the BIOS setup screen,
to see if there is a setting in there, to calm the fan speed earlier
in the boot cycle.

The fan may begin to howl, if any dust filters are clogged, or you
cover the intake vents with a cloth or drapes. So hearing the
"vacuum cleaner noise" is partially a safety feature. It is an
audible warning that there is a cooling problem. But in the bigger
scheme of things, I think the lack of control until *some*
software is loaded, positively stinks. It shows a lack of
designer finesse. Even some Apple products do this...

Paul
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