Intel E5-1600, CM8062101038606, E5-4600 Frequency/SVID Control, Frequency and Voltage Ordering

5.2.2.1Frequency/SVID Control

The processor uses Frequency/SVID control whereby TCC activation causes the processor to adjust its operating frequency (via the core ratio multiplier) and VCC input voltage (via the SVID signals). This combination of reduced frequency and voltage results in a reduction to the processor power consumption.

This method includes multiple operating points, each consisting of a specific operating frequency and voltage. The first operating point represents the normal operating condition for the processor. The remaining points consist of both lower operating frequencies and voltages. When the TCC is activated, the processor automatically transitions to the new lower operating frequency. This transition occurs very rapidly (on the order of microseconds).Once the new operating frequency is engaged, the processor will transition to the new core operating voltage by issuing a new SVID code to the VCC voltage regulator. The voltage regulator must support dynamic SVID steps to support this method. During the voltage change, it will be necessary to transition through multiple SVID codes to reach the target operating voltage. Each step will be one SVID table entry (see Table 7-3). The processor continues to execute instructions during the voltage transition. Operation at the lower voltages reduces the power consumption of the processor.

A small amount of hysteresis has been included to prevent rapid active/inactive transitions of the TCC when the processor temperature is near its maximum operating temperature. Once the temperature has dropped below the maximum operating temperature, and the hysteresis timer has expired, the operating frequency and voltage transition back to the normal system operating point via the intermediate SVID/frequency points. Transition of the SVID code will occur first, to insure proper operation once the processor reaches its normal operating frequency. Refer to Figure 5-33for an illustration of this ordering.

Figure 5-33. Frequency and Voltage Ordering

Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families	139
Datasheet Volume One