GB P35C-DS3R

Using this mobo. No major problem setting it up and running healthy for 3
months already. But has a "minor" problem since Day 1. It had a short "beep"
(say call it Beep A) before the POST beep (call it Beep B). A and B has
different tune. Beep B is almost identical to any previous mobo I have ever
use. Recently, this "minor" problem is getting worse. It became longer and
longer, and happened on and off within 5 minutes of system start up. But it
happened only after cold start up, but not restart. And it won't happen
after the system run for a longer time. At first I though it is just
something wrong with the speaker, which is very close to a fan I added in
front of the case. Yesterday, I opened the case and see what happen. I was
shocked because everytime Beep A happen, no matter long or short, the CPU
fan stop. So Beep A is a warning on this. The minor problem is in fact a
major one.

Why the CPU fan didn't start turning at power up but about 3 seconds
afterward (other case fans also attached to this mobo and they started to
turn immediately after pressing the power)? Why it sometimes stop in the
middle of use (long Beep A) and then stop and then turn again? Anyone has
similar experience or any idea what is going on here please help.

senderj wrote:
Using this mobo. No major problem setting it up and running healthy for 3
months already. But has a "minor" problem since Day 1. It had a short "beep"
(say call it Beep A) before the POST beep (call it Beep B). A and B has
different tune. Beep B is almost identical to any previous mobo I have ever
use. Recently, this "minor" problem is getting worse. It became longer and
longer, and happened on and off within 5 minutes of system start up. But it
happened only after cold start up, but not restart. And it won't happen
after the system run for a longer time. At first I though it is just
something wrong with the speaker, which is very close to a fan I added in
front of the case. Yesterday, I opened the case and see what happen. I was
shocked because everytime Beep A happen, no matter long or short, the CPU
fan stop. So Beep A is a warning on this. The minor problem is in fact a
major one.

Why the CPU fan didn't start turning at power up but about 3 seconds
afterward (other case fans also attached to this mobo and they started to
turn immediately after pressing the power)? Why it sometimes stop in the
middle of use (long Beep A) and then stop and then turn again? Anyone has
similar experience or any idea what is going on here please help.


Does your system feature QST for fan control ?

QST is a scheme that uses features inside the Northbridge and Southbridge.
On older motherboards, the fan interfaces were on the Super I/O chip and
its hardware monitor/fan control interface. QST is not used by all manufacturers,
but some do, and the controls for fans are under microcontroller control,
rather than the system processor. And that means there can be a delay, until the
microcontroller is running its code. You may also find situations,
where QST controlled fans ramp up and down every couple seconds, and
this could be caused by this new control method as well.

This is a short section from the ICH9R datasheet, to show some of the facilities
included for QST fan control. The Northbridge datasheet, doesn't give any details
on its part of the picture. I understand the microcontroller lives in the Northbridge,
and leeches off the system memory, as a place to get RAM space to store its
variables. Some motherboards specify a certain DIMM slot, as the first one
to fill, to help with this QST scheme:

"Intel Quiet System Technology (Intel QST)

The ICH9 integrates four fan speed sensors (four TACH signals) and 3 fan speed
controllers (three Pulse Width Modulator signals), which enables monitoring and
controlling up to four fans on the system. With the new implementation of the
singlewire Simple Serial Transport (SST) 1.0 bus and Platform Environmental Control
Interface (PECI), the ICH9 provides an easy way to connect to SST-based thermal
sensors and access the processor thermal data. In addition, coupled with the new
sophisticated fan speed control algorithms, Intel QST provides effective thermal and
acoustic management for the platform.

Note: Intel Quiet System Technology functionality requires a correctly configured system,
including an appropriate (G)MCH with ME, ME firmware, and system BIOS support."

Try disabling QST. I don't know if that completely takes the microcontroller
out of the picture or not, but it is worth a shot.

HTH,
Paul