Intel Xeon 7130N LF80550KF0878M Data Sheet

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Enhanced Intel SpeedStep Technology enables the processor to switch between multiple frequency 
and voltage points, which may result in platform power savings. In order to support this 
technology, the system must support dynamic VID transitions. Switching between 
voltage/frequency states is software controlled. For more configuration details also refer to the 
Prescott, Nocona and Potomac Processor BIOS Writer’s Guide (BWG).

Not all processors are capable of supporting Enhanced Intel SpeedStep technology. More details on 
which processor frequencies will support this feature will be provided in future releases of the 
NDA Specification Update.

Dynamic VID transitions will only occur if both cores request a lower operating frequency. 
However, only one core has to request a higher frequency for the VID to transition to a higher 
value.

Enhanced Intel SpeedStep Technology is a technology that creates processor performance states 
(P-states). P-states are power consumption and capability states within the Normal state. Enhanced 
Intel SpeedStep technology enables real-time dynamic switching between frequency and voltage 
points. It alters the performance of the processor by changing the bus to core frequency ratio and 
voltage. This allows the processor to run at different core frequencies and voltages to best serve the 
performance and power requirements of the processor and system. Note that the FSB is not altered; 
only the internal core frequency is changed. In order to run at reduced power consumption, the 
voltage is altered in step with the bus ratio. 

The following are key features of Enhanced Intel SpeedStep Technology:

•

Two voltage/frequency operating points provide optimal performance at reduced power 
consumption.

•

Voltage/Frequency selection is software controlled by writing to processor MSR's (Model 
Specific Registers), thus eliminating chipset dependency.

— If the target frequency is higher than the current frequency, Vcc is incremented in steps 

(+12.5 mV) by placing a new value on the VID signals and the processor shifts to the new 
frequency. Note that the top frequency for the processor can not be exceeded.

— If the target frequency is lower than the current frequency, the processor shifts to the new 

frequency and Vcc is then decremented in steps (–12.5 mV) by changing the target VID 
through the VID signals.

Refer to the Prescott, Nocona and Potomac Processor BIOS Writer’s Guide (BWG) for specific 
information to enable and configure Enhanced Intel SpeedStep technology in BIOS. 

The Dual-Core Intel Xeon processor 7000 series package includes an SMBus interface which 
allows access to a memory component with two sections (referred to as the Processor Information 
ROM and the Scratch EEPROM) and a thermal sensor on the substrate. The SMBus thermal sensor 
may be used to read the thermal diode mentioned in 

. These devices and their features 

are described below.

The SMBus thermal sensor and its associated thermal diode are not related to and are completely 
independent of the precision, on-die temperature sensor and TCC of the Thermal Monitor feature 
discussed in 

.