BIOS: Throttle Slow Clock Ratio?

  • Thread starter Thread starter Peter Wagner
  • Start date Start date
P

Peter Wagner

Hi

In the BIOS of my new MB can I adjust the duty cycle in the option
"Power->APM Configuration->Throttle Slow Clock Ratio"
between 87.5% and 12.5%.

What does the Duty Cycle means?
Which values should I select?

TIA
p
 
"Peter Wagner" said:
Hi

In the BIOS of my new MB can I adjust the duty cycle in the option
"Power->APM Configuration->Throttle Slow Clock Ratio"
between 87.5% and 12.5%.

What does the Duty Cycle means?
Which values should I select?

TIA
p
Click to expand...

P4C/P4EE datasheet - page75

ftp://download.intel.com/design/Pentium4/datashts/29864312.pdf

"The TCC may also be activated via On-Demand mode. If bit 4
of the ACPI Thermal Monitor Control Register is written to a 1,
the TCC will be activated immediately independent of the
processor temperature. When using On-Demand mode to activate
the TCC, the duty cycle of the clock modulation is programmable
via bits 3:1 of the same ACPI Thermal Monitor Control Register.
In automatic mode, the duty cycle is fixed. However, in On-Demand
mode, the duty cycle can be programmed from 12.5% on/87.5% off,
to 87.5% on/12.5% off in 12.5% increments. On-Demand mode may be
used at the same time Automatic mode is enabled. However, if the
system tries to enable the TCC via On-Demand mode at the same
time automatic mode is enabled AND a high temperature condition
exists, the duty cycle of the automatic mode will override the
duty cycle selected by the On-Demand mode."

Roughly translated, what this means is, _if_ the OS has an ACPI
object that is in charge of monitoring the processor's temperature,
that OS can command the processor to reduce its processing rate.
The BIOS entry allows the user to specify what percentage slowdown
to use, if ACPI decides the processor is too hot.

Since there is also an automated function inside the processor,
that does the same thing at 70C, there isn't too much value to
this function, unless maybe you wanted a throttling response
at some lower temperature. If you set this, I would use an
aggressive setting, so you will notice when it is being used.
If set to 12.5%, I think that means only 1 cycle in 8 is used
for computing, which should make the processor at lot cooler
in an emergency.

There is a third function, that shuts the processor off at
135C die temperature. That is what would be activated if the
heatsink fell off, as in that case, thermal throttling would
not be enough to control the temperature.

HTH,
Paul
 
Paul

Thank you very much for your answer and the link.
P4C/P4EE datasheet - page75

ftp://download.intel.com/design/Pentium4/datashts/29864312.pdf
Click to expand...
Roughly translated, what this means is, _if_ the OS has an ACPI
object that is in charge of monitoring the processor's temperature,
that OS can command the processor to reduce its processing rate.
The BIOS entry allows the user to specify what percentage slowdown
to use, if ACPI decides the processor is too hot.

Since there is also an automated function inside the processor,
that does the same thing at 70C, there isn't too much value to
this function, unless maybe you wanted a throttling response
at some lower temperature. If you set this, I would use an
aggressive setting, so you will notice when it is being used.
If set to 12.5%, I think that means only 1 cycle in 8 is used
for computing, which should make the processor at lot cooler
in an emergency.

There is a third function, that shuts the processor off at
135C die temperature. That is what would be activated if the
heatsink fell off, as in that case, thermal throttling would
not be enough to control the temperature.
Click to expand...

Sorry, but I'm to dumb to understand the whole matter. :-(
I've got an ASUS P4P800-E Deluxe with a P4-3200, which consumes a lot of
power.
To save power I switch to the Standby mode S3 (WinXP), if I'm making a
break.
So the saving of power is about a 90%.
My question is, it's important to set the duty cycle to 12.5% or to
87.5% for the best power saving?
That's all.
HTH,
Paul
Click to expand...

p
 
"Peter Wagner" said:
Paul

Thank you very much for your answer and the link.
Click to expand...
Sorry, but I'm to dumb to understand the whole matter. :-(
I've got an ASUS P4P800-E Deluxe with a P4-3200, which consumes a lot of
power.
To save power I switch to the Standby mode S3 (WinXP), if I'm making a
break.
So the saving of power is about a 90%.
My question is, it's important to set the duty cycle to 12.5% or to
87.5% for the best power saving?
That's all.


p
Click to expand...

Try 12.5%, then check with dumppo.exe (see bottom of this post).

The duty cycle setting is _only_ used when the processor
is running and is not used when the computer is in S3 standby
state. The purpose of the duty cycle control is to control the
temperature, if the processor is overheating, and if the cooling
of the processor is sufficient, the duty cycle will never be
used by ACPI.

If you are in S3, that is Suspend to RAM (STR). In STR, only the
RAM in the computer is powered. The processor and disk are turned
off. STR burns perhaps 5W-10W when it is running. The PSU fan will
be off in STR (otherwise known as ACPI S3 state).

There are other suspend states, such as S1, where the video output
is disabled and the disk spins down. That saves hardly any power
at all. The PSU fan continues to run in S1, as does the processor,
so little power is saved at all.

Be careful that you are not mixing up S1 and S3, as S3 does save
power, while S1 doesn't do much for you.

For S3 to be properly installed:

Section 4.5.1 in manual - make sure "Suspend Mode" is not set to
S1 only. Try the Auto setting.

Install the OS with the ACPI HAL. You can check this in the Device
Manager. The Computer entry should say "ACPI" and not "Standard PC".
ACPI is necessary for S3 to work.

http://www.dewassoc.com/support/win2000/tshoot_hal.htm

You can also use the dumppo.exe utility, to configure the OS
to use S3 for Standby. Dumppo is a command line Microsoft
utility, used to set up S states, if there is some problem with
them. As long as ACPI is installed, and the BIOS has enabled
support for S3 (STR), it should work with the "admin" command.

ftp://ftp.microsoft.com/Products/Oemtest/v1.1/WOSTest/Tools/Acpi/dumppo.exe

From a DOS prompt (command window):

dumppo ps cap # This dumps the ACPI object information
# It says whether S1 or S3 are supported
# If S3 is listed as supported, you do not
# need the following command.

dumppo admin /ac maxsleep=S3 # This admin override, adds S3, as
# long as an ACPI HAL is being used.

The options for dumppo.exe are:

cap power abilities
ps Win32 System power status
bs battery status
admin Admin policy overrides
ac AC power policy
dc DC power policy

HTH,
Paul
 
Paul

Thank you very much for your answer and the URL.

Try 12.5%, then check with dumppo.exe (see bottom of this post).

The duty cycle setting is _only_ used when the processor
is running and is not used when the computer is in S3 standby
state. The purpose of the duty cycle control is to control the
temperature, if the processor is overheating, and if the cooling
of the processor is sufficient, the duty cycle will never be
used by ACPI.
Click to expand...

Thanks for your explanation.
I thought the CPU will switch off at about 80° with or w/o the duty
cycle control?!
If you are in S3, that is Suspend to RAM (STR). In STR, only the
RAM in the computer is powered. The processor and disk are turned
off. STR burns perhaps 5W-10W when it is running. The PSU fan will
be off in STR (otherwise known as ACPI S3 state).
Click to expand...

Yes, I've selected S3 in the BIOS.
It works very good.
The only lack is that one can't switch with the space key.
There are other suspend states, such as S1, where the video output
is disabled and the disk spins down. That saves hardly any power
at all. The PSU fan continues to run in S1, as does the processor,
so little power is saved at all.

Be careful that you are not mixing up S1 and S3, as S3 does save
power, while S1 doesn't do much for you.

For S3 to be properly installed:

Section 4.5.1 in manual - make sure "Suspend Mode" is not set to
S1 only. Try the Auto setting.

Install the OS with the ACPI HAL. You can check this in the Device
Manager. The Computer entry should say "ACPI" and not "Standard PC".
ACPI is necessary for S3 to work.
Click to expand...

Yes, it's ok.
http://www.dewassoc.com/support/win2000/tshoot_hal.htm

You can also use the dumppo.exe utility, to configure the OS
to use S3 for Standby. Dumppo is a command line Microsoft
utility, used to set up S states, if there is some problem with
them. As long as ACPI is installed, and the BIOS has enabled
support for S3 (STR), it should work with the "admin" command.

ftp://ftp.microsoft.com/Products/Oemtest/v1.1/WOSTest/Tools/Acpi/dumppo.exe
Click to expand...

Thanks.
I'll try it.
HTH,
Paul
Click to expand...

p
 
Back
Top