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produce any noise. Use the “passive cooling trip point” setup node in the BIOS setup program to determine the temperature threshold that the
operating system will use to start or stop the passive cooling procedure.
•
Active Cooling
During this cooling policy the operating system is turning the fan on/off. Although active cooling devices consume power and produce noise,
they also have the ability to cool the thermal zone without having to reduce the overall system performance. Use the “active cooling trip point”
setup node in the BIOS setup program to determine the temperature threshold that the operating system will use to start the active cooling
device. It is stopped again when the temperature goes below the threshold (4°C hysteresis).
•
Critical Trip Point
If the temperature in the thermal zone reaches a critical point then the operating system will perform a system shut down in an orderly fashion
in order to ensure that there is no damage done to the system as result of high temperatures. Use the “critical trip point” setup node in the BIOS
setup program to determine the temperature threshold that the operating system will use to shut down the system.
Note
The end user must determine the cooling preferences for the system by using the setup nodes in the BIOS setup program to establish the
appropriate trip points.
If passive cooling is activated and the processor temperature is above the trip point the processor clock is throttled according to the formula
below.
∆P[%] = TC1(T
n
-T
n-1
) + TC2(T
n
-T
t
)
•
∆P is the performance delta
•
T
t
is the target temperature = critical trip point
•
The two coefficients TC1 and TC2 and the sampling period TSP are hardware dependent constants. These constants are set to fixed values
for the conga-TCA:
•
TC1= 1
•
TC2= 5
•
TSP= 5 seconds
See section 12 of the ACPI Specification 2.0 C for more information about passive cooling.
