Ampro Corporation COM 830 manual Processor Performance Control, Intel

Chapter 2 Specifications

any damage to the processor as a result of overheating. The THERMTRIP# signal activation is completely independent from processor activity and therefore does not produce any bus cycles.

NOTE In order for THERMTRIP# to be able to automatically switch off the system it is necessary to use an ATX style power supply.

Processor Performance Control

Intel® Core™ 2 Duo and 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.

NOTE 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 Ampro 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 2 Duo and 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 that 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 this leads to a performance decrease of approximately 25%.

Intel 64

The formerly known Intel Extended Memory 64 Technology is an enhancement to Intel's IA-32 architecture. Intel 64 is only available on Core 2 Duo processors and is designed to run newly written 64-bit code and access more than 4GB of memory. Processors with Intel 64 architecture support 64-bit-capable operating systems from Microsoft and Red Hat. Processors running in legacy mode remain fully compatible with today's existing 32-bit applications and operating systems.

Platforms with Intel 64 can be run in three basic ways:

1.Legacy Mode: 32-bit operating system and 32-bit applications. In this mode no software changes are required, however the benefits of Intel 64 are not utilized.

2.Compatibility Mode: 64-bit operating system and 32-bit applications. This mode requires all device drivers to be 64-bit. The operating system will see the 64-bit extensions but the 32-bit application will not. Existing 32-bit applications do not need to be recompiled and may or may not benefit from the 64- bit extensions. The application will likely need to be re-certified by the vendor to run on the new 64-bit extended operating system.

20 Reference Manual COM 830