Thermal Specifications and Design Considerations

With a properly designed and characterized thermal solution, it is anticipated that the TCC would only be activated for very short periods of time when running the most power intensive applications. The processor performance impact due to these brief periods of TCC activation is expected to be so minor that it would be immeasurable. An under-designed thermal solution that is not able to prevent excessive activation of the TCC in the anticipated ambient environment may cause a noticeable performance loss, and in some cases may result in a TC that exceeds the specified maximum temperature and may affect the long-term reliability of the processor. In addition, a thermal solution that is significantly under-designed may not be capable of cooling the processor even when the TCC is active continuously. Refer to the Intel® Pentium® D Processor and Intel® Pentium® Processor Extreme Edition 840 Thermal and Mechanical Design Guidelines for information on designing a thermal solution.

The duty cycle for the TCC, when activated by the Thermal Monitor, is factory configured and cannot be modified. The Thermal Monitor does not require any additional hardware, software drivers, or interrupt handling routines.

5.2.2On-Demand Mode

The Pentium D processor provides an auxiliary mechanism that allows system software to force the processor to reduce its power consumption. This mechanism is referred to as "On-Demand" mode and is distinct from the Thermal Monitor feature. On-Demand mode is intended as a means to reduce system level power consumption. Systems using the Pentium D processor must not rely on software usage of this mechanism to limit the processor temperature.

If bit 4 of the ACPI P_CNT Control Register (located in the processor IA32_THERM_CONTROL MSR) is written to a '1', the processor will immediately reduce its power consumption via modulation (starting and stopping) of the internal core clock, independent of the processor temperature. When using On-Demand mode, the duty cycle of the clock modulation is programmable via bits 3:1 of the same ACPI P_CNT Control Register. 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 in conjunction with the Thermal Monitor. If the system tries to enable On-Demand mode at the same time the TCC is engaged, the factory configured duty cycle of the TCC will override the duty cycle selected by the On-Demand mode.

5.2.3PROCHOT# Signal

An external signal, PROCHOT# (processor hot), is asserted when the processor core temperature has reached its maximum operating temperature. If the Thermal Monitor is enabled (note that the Thermal Monitor must be enabled for the processor to be operating within specification), the TCC will be active when PROCHOT# is asserted. The processor can be configured to generate an interrupt upon the assertion or de-assertion of PROCHOT#. Refer to the Intel Architecture Software Developer's Manuals for specific register and programming details.

For the Pentium D processor, PROCHOT# can be configured via BIOS as an output or a bi- directional signal. As an output, PROCHOT# (Processor Hot) will go active when the processor temperature monitoring sensor detects that one or both cores has reached its maximum safe operating temperature. This indicates that the processor Thermal Control Circuit (TCC) has been activated, if enabled. As an input, assertion of PROCHOT# by the system will activate the TCC, if enabled, for both cores. The TCC will remain active until the system de-asserts PROCHOT#.

If PROCHOT# is configured as an output only, the FORCEPR# signal can be driven from an external source to activate the TCC. This will prevent one core from asserting the PROCHOT# signal of the other core and unnecessarily activating the TCC of that core. Refer to Section 5.2.4 for details on the FORCEPR# signal.

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Intel 830 manual On-Demand Mode, PROCHOT# Signal

830 specifications

The Intel 830 chipset, introduced in the early 2000s, marked a significant evolution in Intel's chipset architecture for desktop and mobile computing. Known for its support of the Pentium 4 processors, the 830 chipset was tailored for both performance and stability, making it an appealing choice for OEMs and enthusiasts alike.

One of the standout features of the Intel 830 chipset is its support for DDR SDRAM, providing a much-needed boost in memory bandwidth compared to its predecessors. With dual-channel memory support, the chipset could utilize two memory modules simultaneously, which effectively doubled the data transfer rate and enhanced overall system performance. This made the Intel 830 particularly beneficial for applications requiring high memory throughput, such as multimedia processing and gaming.

Another important characteristic of the Intel 830 was its integrated graphics support, featuring Intel's Extreme Graphics technology. This integration allowed for decent graphics performance without the need for a dedicated GPU, making it suitable for budget systems and everyday computing tasks. However, for power users and gaming enthusiasts, the option to incorporate a discrete graphics card remained available through the provided PCI Express x16 slot.

The Intel 830 chipset also boasted advanced I/O capabilities, including support for USB 2.0, which provided faster data transfer rates compared to USB 1.1, and enhanced IDE interfaces for connecting hard drives and optical devices. With its Hyper-Threading technology support, the chipset allowed for improved multitasking efficiency, enabling a single processor to execute multiple threads simultaneously, a feature that was particularly beneficial in server environments and complex computing tasks.

In terms of connectivity, the Intel 830 supported multiple bus interfaces, including PCI Express and AGP, thereby enabling users to expand their systems with various add-on cards. This flexibility contributed to the chipset's longevity in the marketplace, as it catered to a wide range of user needs from light computing to intensive gaming and content creation.

In summary, the Intel 830 chipset combined enhanced memory capabilities, integrated graphics performance, robust I/O features, and flexible expansion options, making it a versatile choice for various computing environments during its time. It played a key role in shaping the landscape of early 2000s computing, paving the way for future advancements in chipset technology. Its legacy continues to influence modern computing architectures, illustrating the lasting impact of Intel’s innovative design principles.