User manual

Kontron Compact Computers AG SMX945 Detailed Manual V1.1
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8. DETAILED SPECIFICATIONS
Note...
On the following pages are design-in recommendations taken from various Intel manuals.
8.1. Intel Core Duo Processors
Intel
®
Core™ Duo processors run at different voltage/frequency states (performance states), which is
referred to as Enhanced Intel
®
SpeedStep
®
technology (EIST). Operating systems that support performance
control take advantage of microprocessors that use several different performance states in order to efficiently
operate the processor when it is not being fully utilized.
The operating system will determine the necessary performance state that the processor should run at so
that the optimal balance between performance and power consumption can be achieved during runtime. The
Windows family of operating systems links its processor performance control policy to the power scheme
setting found in the control panel option applet.
If the “Home/Office” or “Always On” power scheme is selected when using Windows operating systems, then
the processor will always run at the highest performance state. For more information about this subject see
Chapter 8 of the ACPI Specification Revision 2.0c, which can be found at www.acpi.info . Also, visit
Microsoft's website and search for the document called “Windows Native Processor Performance Control”.
The BIOS allows you to limit the maximum processor frequency. This can be useful if the maximum
performance is not required or if the maximum processor performance state dissipates too much power and
heat.
In the “CPU Configuration” submenu of the “BIOS Setup Program” you'll find the node for “Max. Frequency”
limitation. For each Intel
®
Core™ Duo processor, the BIOS lists the supported frequencies. If a lower
frequency than the maximum one is selected, the processor will never run at frequencies above this setting.
Celeron M processors do not support Enhanced Intel
®
SpeedStep
®
technology; they always run at a fixed
frequency. In order to limit the performance and power consumption of Celeron M processors, the BIOS
offers “On-Demand Clock Modulation” support in the “CPU Configuration” submenu of the “BIOS Setup
Program”.
When “On-Demand Clock Modulation” is enabled, the processor clock is throttled using the duty cycle
determined in setup. Keep in mind that the “On-Demand” clock modulation duty cycle indicates the clock-on
to clock-off interval ratio. This means that when set to 75% the clock is running 75% of the overall time and
leads to a performance decrease of approximately 25%.
With the Celeron M 440 (1.86GHz CPU), the power consumption decreases approximately 3W when set to
75% duty cycle and 6W when set to 50% duty cycle.