While trying to find out what temperature reading, wether TCase or core temps, is related to the maximum safe operating temperature for my FX6100 (stated at 70C max) I emailed AMD tech support and received the following response:

From: TECH.SUPPORT@AMD.COM

Sent: Mon 5/07/12 1:24 PM

To: xxxxxxxxxxxxxxx@hotmail.com


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Dear Stephen,

Your service request : SR #{ticketno:[8200488157]} has been reviewed and updated.

Response and Service Request History:

I understand that you are looking for clarity about the 70c maximum operating temperature of the FX-6100 and which specific temperature it references at that point. If this is incorrect, please let me know as the information provided may change.

The maximum operating temperatures for any AMD CPU is measured as TCase, as we find that the actual temperature measured by a thermistor inside the processor is a much more accurate measurement of the processor's temperature. While TJunction is helpful in determining the temperature of the actual pins that are transmitting the data, the fact that every pin doesn't fire at exactly the same time, the results can be somewhat skewed. While we don't have the tech docs up for the FX series yet in terms of max temperatures, you can see that we post TCase maximum temperatures on our Athlon/Sempron/Phenom processor Tech Docs at http://support.amd.com/us/Processor_TechDocs/43375.pdf , instead of using TJunction/TJ/TCore/etc.

As for Tctl, there is a technical definition at http://support.amd.com/us/Processor_TechDocs/41256.pdf on page 73 that (tries to) explain it. As a very crude Cole's Notes version, it doesn't measure temperature as much as it is a sliding scale that refers to the processor's current temperature as it relates to the temperature at which the cooling fan has to get to 100% to hit the maximum case temperature (TCaseMax). Confusing I know, but it allows the system to see how close it is to hitting 100% and subsequently it has to start slowing things down to get the temperature down. It is usually close to Tcase Max, but is more a point of reference for how close it is getting to Tcase Max, or if it is past that point and by how much. Things run normally at Tctl < TCaseMax - 0.125, and when it hits TCaseMax or higher, then things start getting shut down/slowed down/etc to get the temperature down. I hope that makes some semblance of sense, as it took a bit to wrap my head around it.

We appreciate your loyalty to AMD as we continue to strive for the best products in terms of graphics and processors for our customers. I am glad to hear that you are enjoying your FX 6100, and hope that the joy will continue for years to come. If you have any other questions or comments, please don't hesitate to reply directly to this email and I will try to provide any additional information that you may require.

In order to update this service request, please respond, leaving the service request reference intact.

Best regards,

AMD Global Customer Care