Intel X5460 AT80574KJ087N Data Sheet

Product codes
AT80574KJ087N
Page of 118
Thermal Specifications
92
The second operating point consists of both a lower operating frequency and voltage. 
The lowest operating frequency is determined by the lowest supported bus ratio (1/6 
for the Quad-Core Intel® Xeon® Processor 5400 Series). When the TCC is activated, 
the processor automatically transitions to the new frequency. This transition occurs 
rapidly, on the order of 5 µs. During the frequency transition, the processor is unable to 
service any bus requests, and consequently, all bus traffic is blocked. Edge-triggered 
interrupts will be latched and kept pending until the processor resumes operation at the 
new frequency.
Once the new operating frequency is engaged, the processor will transition to the new 
core operating voltage by issuing a new VID code to the voltage regulator. The voltage 
regulator must support dynamic VID steps in order to support Intel® Thermal Monitor 
2. During the voltage change, it will be necessary to transition through multiple VID 
codes to reach the target operating voltage. Each step will be one VID table entry (see 
). The processor continues to execute instructions during the voltage 
transition. Operation at the lower voltage 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. Transition of the VID code 
will occur first, in order to insure proper operation once the processor reaches its 
normal operating frequency. Refer to 
 for an illustration of this ordering.
The PROCHOT# signal is asserted when a high temperature situation is detected, 
regardless of whether Intel® Thermal Monitor 1 or Intel® Thermal Monitor 2 is 
enabled.
6.2.2
On-Demand Mode
The 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 Intel® Thermal Monitor 1 and Intel® Thermal 
Monitor 2 features. On-Demand mode is intended as a means to reduce system level 
power consumption. Systems utilizing the Quad-Core Intel® Xeon® Processor 5400 
Figure 6-7. Intel® Thermal Monitor 2 Frequency and Voltage Ordering
Vcc
Temperature
V
NOM
Frequency
Time
f
TM2
f
MAX
T
TM2
V
TM2
T(hysterisis)
Vcc
Temperature
V
NOM
Frequency
Time
f
TM2
f
MAX
T
TM2
V
TM2
T(hysterisis)