Intel ETX CD manual Processor Performance Control, Summary, Active Cooling

7 Important Technology Information

Automatic mode does not require any additional hardware, software drivers, or interrupt handling routines.

Note:	With a properly designed thermal solution, the TCC is only active for very short periods, hence processor
	performance impact is expected to be so minor that it would not be detectable.

The Intel® Core Duo® and Core2Duo® processors support the THERMTRIP# signal for catastrophic thermal protection.

In the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon has reached a temperature of approximately 125°C. At this point the system BUS signal THERMTRIP# will go active.

THERMTRIP# activation is independent of processor activity and does not generate any bus cycles.

7.2.1Summary

Thermal Control Circuit reduces performance when the processor reaches its max. operating temperature (100°C). THERMTRIP# shuts down the system in case of catastrophic cooling failure.

7.3Processor Performance Control

The Intel® Core Duo® and Core2Duo® processors run in different performance states (multiple frequency/voltage operating points). The CPU performance can be altered while the computer is functioning. This allows the processor to run at different core frequencies and voltages depending on CPU thermal state and OS policy.

Windows XP includes built-in processor performance control to operate the processor more efficiently when it is not fully utilized. Win2k, WinME and Win9x do not support processor performance control. Special software is required for Oses not capable of processor performance control.

In Windows, the processor performance control policy is linked to the Power Scheme setting in the control panel power option applet.

Note:	Windows always runs at the highest performance state when the “Home/Office” or “Always On” power
	scheme is selected.
	For a more detailed information about processor performance control, see:
	Chapter 8 of the ACPI Specification Revision 2.0c available at www.acpi.info Windows platform design note
	at: http://www.microsoft.com/whdc/hwdev/tech/onnow/procperfctrl.mspx

7.4Thermal Management

ACPI allows the OS to play a role in the thermal management of the system. With the OS in control of the operating environment, cooling decisions can be made based on the application load on the CPU and the thermal heuristics of the system.

The ACPI thermal solution on ETX®-CD supports three cooling policies:

Active Cooling

The OS is turning the fan on/off. Active cooling devices typically consume power and produce noise, but are able to cool a thermal zone without limiting system performance. The active cooling trip point

Kontron User's Guide ETX CD 44