Features
Note:
Not all Dual-Core Intel Xeon Processor 5000 series 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 Dual-Core Intel® Xeon® Processor
5000 Series Specification Update when available.
Enhanced Intel SpeedStep Technology creates processor performance states (P-states)
or voltage/frequency operating points. P-states are lower power capability states within
the Normal state as shown in Figure 7-1. 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. The
Dual-Core Intel Xeon Processor 5000 series have hardware logic that coordinates the
requested processor voltage between the processor cores. The highest voltage that is
requested for either of the processor cores is selected for that processor. Note that the
front side bus 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:
• Multiple 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.
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Dual-Core Intel® Xeon® Processor 5000 Series Datasheet
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INTEL [ INTEL ]
