2.10 Thermal Functions
Thermal functions HTC, STC and THERMTRIP are intended to maintain processors temperature in a valid
• Providing an input to the external circuitry that controls cooling.
• Lowering power consumption by switching to lower-performance P-state or.
• Sending processor to the THERMTRIP state to prevent it from damage.
The processor thermal-related circuitry includes (1) the temperature calculation circuit (TCC) for determining
the temperature of the processor and (2) logic that uses the temperature from the TCC. The processor includes
a thermal diode as well.
2.10.1 The Tctl Temperature Scale
Tctl is the processor temperature control value, used by the platform to control cooling systems. Tctl is accessible
through SB-TSI and F3xA4[CurTmp]. Tctl is a non-physical temperature on an arbitrary scale measured in
degrees. It does not represent an actual physical temperature like die or case temperature. Instead, it specifies
the processor temperature relative to the point at which the system must supply the maximum cooling for the
processor’s specified maximum case temperature and maximum thermal power dissipation. It is defined as follows
for all parts:
• For Tctl = 0 to Tctl_max - 0.125: the temperature of the part is [Tctl_max - Tctl] degrees under the temperature
for which maximum cooling is required.
• For Tctl = Tctl_max to 255.875: the temperature of the part is [Tctl - Tctl_max] degrees over the worst-case
expected temperature under normal conditions. The processor may take corrective actions that affects performance
or operation as a result, such as invoking HTC or THERMTRIP_L.
Well, I am looking for a relatively simple method, technique, settings or any tool to determine, under some circumstances, when (I mean, for which value of Tctl), these thermal safety functions are actually activated (The processor may take corrective actions that affects performance or operation as a result, such as invoking HTC or THERMTRIP_L).
For a first quick'n'dirty survey I've used some popular tools for Windows OSes (I've used CPU-Z 1.57, RMClock 2.3.5 and Throttle Watch 2.02 to detect any clock changing, and also I used two more tools, Core Temp and SpeedFan, for temperature readings, while I used Mersenne Prime95 to heat up the CPUs), but for some unknown reason I'm not able to actually detect any change in cores clock frequency, expectedly due to thermal throttle (currently on three AMD 10h CPUs, a Phenom II X4 980, an Athlon II X4 605e, and an Athlon II X3 420e) up to 103° C "reported" core's temperature. So now I think there is some methodological flaw in mine actions.
Please forgive me for my not so good english, and thanks in advance for any hints.