Intel X5460 AT80574KJ087N Data Sheet

Product codes
AT80574KJ087N
Page of 118
93
Thermal Specifications
Series must not rely on software usage of this mechanism to limit the processor 
temperature. If bit 4 of the IA32_CLOCK_MODULATION MSR is set to a ‘1’, the 
processor will immediately reduce its power consumption via modulation (starting and 
stopping) of the internal core clock, independent of the processor temperature. When 
using On-Demand mode, the duty cycle of the clock modulation is programmable via 
bits 3:1 of the same IA32_CLOCK_MODULATION MSR. In On-Demand mode, the duty 
cycle can be programmed from 12.5% on/ 87.5% off to 87.5% on/12.5% off in 12.5% 
increments. On-Demand mode may be used in conjunction with the Thermal Monitor; 
however, if the system tries to enable On-Demand mode at the same time the TCC is 
engaged, the factory configured duty cycle of the TCC will override the duty cycle 
selected by the On-Demand mode.
6.2.3
PROCHOT# Signal
An external signal, PROCHOT# (processor hot) is asserted when the processor die 
temperature of any processor cores reaches its factory configured trip point. If Thermal 
Monitor is enabled (note that Thermal Monitor must be enabled for the processor to be 
operating within specification), the TCC will be active when PROCHOT# is asserted. The 
processor can be configured to generate an interrupt upon the assertion or de-
assertion of PROCHOT#. Refer to the Intel® 64 and IA-32 Architectures Software 
Developer’s Manual 
for specific register and programming details.
PROCHOT# is designed to assert at or a few degrees higher than maximum T
CASE
 when 
dissipating TDP power, and cannot be interpreted as an indication of processor case 
temperature. This temperature delta accounts for processor package, lifetime and 
manufacturing variations and attempts to ensure the Thermal Control Circuit is not 
activated below maximum T
CASE
 when dissipating TDP power. There is no defined or 
fixed correlation between the PROCHOT# trip temperature, or the case temperature. 
Thermal solutions must be designed to the processor specifications and cannot be 
adjusted based on experimental measurements of T
CASE
, or PROCHOT#.
6.2.4
FORCEPR# Signal
The FORCEPR# (force power reduction) input can be used by the platform to cause the 
Quad-Core Intel® Xeon® Processor 5400 Series to activate the TCC. If the Thermal 
Monitor is enabled, the TCC will be activated upon the assertion of the FORCEPR# 
signal. Assertion of the FORCEPR# signal will activate TCC for all processor cores. The 
TCC will remain active until the system deasserts FORCEPR#. FORCEPR# is an 
asynchronous input. FORCEPR# can be used to thermally protect other system 
components. To use the VR as an example, when FORCEPR# is asserted, the TCC 
circuit in the processor will activate, reducing the current consumption of the processor 
and the corresponding temperature of the VR.
It should be noted that assertion of FORCEPR# does not automatically assert 
PROCHOT#. As mentioned previously, the PROCHOT# signal is asserted when a high 
temperature situation is detected. A minimum pulse width of 500 µs is recommended 
when FORCEPR# is asserted by the system. Sustained activation of the FORCEPR# 
signal may cause noticeable platform performance degradation.
Refer to the appropriate platform design guidelines for details on implementing the 
FORCEPR# signal feature.