There is a good write up on using under the CPU temperature measurement for determining die temperature at the AMD website. The document is 24288.pdf and the title is "Methodologies for Measuring Temperature on AMD Athlon (r) and Duron (r) Processors". They are demonstrating this using an air cooled setup , and in order to get an "accurate " die temperature, they use a formula that requires the ambient temperature from a second sensor mounted just above the fan/heatsink in the air flow of the fan. One thing I've always wondered about is when using a water cooled setup, if the water temperature should be used for the "ambient" temperature in this formula. It should be noted that this formula depends on the thermal resistance characteristics of the ceramic package used for these processors and that the current processors do not use ceramic packages. However, I'd be suprised if this information is not available somewhere on the AMD site.