Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

My friend and I both have the P4C800-E Delixe MB, but we have
different power supplies, I have the Enermax 470w and my friend has a
standard 350w wich came with his case. Both of our systems are
getting minimal air blowing out through the powersupply (Fans are
working in the ps), Now mine is brand new and they both cant be
dieing. I have gone to the Enermax site about mine and in their FAQ
page it does say that the BIOS will automatically control the speed or
you can put it on manual, Q-Fan control has been dissabled in the BIOS
but I have tried playing with some settings on my system and I get no
difference in air speed. Mine also has the manual speed control knob
on the back on the ps and I have set that to max. Is there something
else in the bios which controls the fan speeds??? Thanks

Dman

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <meici0dvttfec28vnavtjrjlii2jjbserk@4ax.com>, Dman@isp.com wrote:

> My friend and I both have the P4C800-E Delixe MB, but we have
> different power supplies, I have the Enermax 470w and my friend has a
> standard 350w wich came with his case. Both of our systems are
> getting minimal air blowing out through the powersupply (Fans are
> working in the ps), Now mine is brand new and they both cant be
> dieing. I have gone to the Enermax site about mine and in their FAQ
> page it does say that the BIOS will automatically control the speed or
> you can put it on manual, Q-Fan control has been dissabled in the BIOS
> but I have tried playing with some settings on my system and I get no
> difference in air speed. Mine also has the manual speed control knob
> on the back on the ps and I have set that to max. Is there something
> else in the bios which controls the fan speeds??? Thanks
>
> Dman

You should state the exact model number of your PSU, to make it
easier to understand what is happening.

The product pages starts here:
http://www.enermax.com.tw/products.php

This Enermax page is one of their FAQ pages:
http://www.enermax.com.tw/quingu.php

If your PSU is "ATX 12V 1.3Version | AX(G)(W)FMA Series"
the product page is here:

http://www.enermax.com.tw/products [...] 18&Gid2=40

This power supply has a two pin fan header. A two pin fan header has
the RPM signal and GND, and that allows the motherboard to _measure_
the PSU fan speed but not control it.

http://www.enermax.com.tw/1.3Vcable_En.htm

When you build a computer, the PSU fan is not sufficient to cool
the computer case. The reason for this, is the PSU is designed for
quiet operation, and the PSU designer will allow the PSU internal
air temperature to be much higher than you would normally want
the computer case air to be. This means the case fans will be running
full blast, well before the PSU fan begins to pick up speed via
its internal temperature controller.

The most critical thing in your computer, is the disk drive. If room
air is 25C, and case air is 32C, then the case of the disk drive has
to be warmer than that. In summer, a computer case like this will
probably cause the disk case temperature to be higher than is good
for the drive, and that is the reason for adding fans to the computer
case.

The CPU temperature is less of an issue, relatively speaking. For
example, a reasonable limit for an AthlonXP is probably around 65C,
and the CPU doesn't need to be chilled to the same extent that the
disk drives do. So, while a fancy cooler for the CPU is nice to have,
it isn't as essential as keeping the disk drive temperature low.
The disk drive will die very quickly, if it receives too much heat
or humidity.

Of course, adding fans to the computer case, creates noise. So
while the PSU designer is absolved from having made the computer
case noisy, if you have a hot processor in the computer, you have
to add fans to keep the air temp in the case low enough to make
the disk drives comfortable. That noise is unavoidable without a
lot of extra cooling design work (water blocks, fancy cases etc).
The case fans can be controlled by a digidoc5, a rheobus, or other
control device, so that they only become noisy while you are gaming
and not while the computer is sitting idle in the desktop.

http://www.tomshardware.com/howto/20040615/index.html

The typical Asus motherboard only has fan speed control for the
CPU fan header. The Q-fan function on the motherboard, controls
the CPU fan speed, and when enabled, Q-fan causes the CPU fan to
speed up when the CPU hits 50C. This function has nothing to do
with the PSU fan or the case fan, and the control of those fans
is a separate issue.

http://usa.asus.com/products/mb/qfan.htm

HTH,
Paul