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Higher Thermal Power Loss Of Up To 130 Watts, Continued

The Mother of All CPU Charts 2005/2006
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The following tables list the thermal dissipation classes for the various CPU series. Note that the dual core series have a higher TDP of up to 130 watts, despite using the same PRB number.

Processor Model Number (500 Series) Platform/PRB/TDP
570/570J/571 04B / PRB = 1 / 115 W
560/560J/561 04B / PRB = 1 / 115 W
550 04B / PRB = 1 / 115 W
550/550J/551 04A / PRB = 0 / 84 W
540/540J/541 04A / PRB = 0 / 84 W
530/530J/531 04A / PRB = 0 / 84 W
520/520J/521 04A / PRB = 0 / 84 W
Platform Compatibility Tcase
04B (PRB = 1) 72.8 °C
04A (PRB = 0) 67.7 °C
Key
Performance Requirement Bit PRB
Platform Compatibility 04A/04B/05A/05B
Thermal Design Power TDP [W]
Processor Model Number (600 Series) Platform/PRB/TDP
Extreme Edition 04B / PRB = 1 / 115 W
670 04B / PRB = 1 / 115 W
660 04B / PRB = 1 / 115 W
650 04A / PRB = 0 / 84 W
640 04A / PRB = 0 / 84 W
630 04A / PRB = 0 / 84 W
Platform Compatibility Tcase
04B (PRB = 1) 70.8 °C
04A (PRB = 0) 66.6 °C
Processor Model Number (800 Series) Platform/PRB/TDP
Extreme Edition 05B / PRB = 1 / 130 W
840 05B / PRB = 1 / 130 W
830 05B / PRB = 1 / 130 W
820 05A / PRB = 0 / 95 W
Platform Compatibility Tcase
04B (PRB = 1) 69.8 °C
04A (PRB = 0) 64.1 °C

In an effort to reduce costs, a number of motherboard manufacturers designed boards that only support the VRM Spec 9.1. These boards are unable to supply enough current for CPUs that belong to a higher performance requirement category.


Beware: Some less expensive motherboards are only equipped for platform compatibility 04A. Manufacturers state the compatibility level in their products' technical specification. In this example, both 04A and 04B are supported.

Intel introduced the Performance Requirement Bit (PRB) to protect the voltage regulation modules on motherboards from overstress as a result of inserting a CPU from a higher performance class into the socket. The PRB is defined in the VRD (Voltage Regulator Down) specification that Intel developed for this specific case.

The VRD Spec was primarily defined to protect the voltage regulation modules on motherboards.

This is what VRD is supposed to prevent: The fixed voltage regulators on this board died a smoky death from overheating.

With the help of a circuit defined in the VRD spec, the Performance-Bit (ForcePR#) can be set if the fixed voltage regulators overheat during operation. This forces the CPU to switch to a multiplier of 14x, reducing energy consumption. Simultaneously, the core voltage is lowered through the fixed voltage regulators.

Intel provides an example of how motherboard manufacturers can implement the protection circuit (Force PR#) on their boards.
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