Intel defines TDP as follows: The upper point of the thermal profile consists of the Thermal Design
Power (TDP) and the associated Tcase value. Thermal Design Power (TDP) should be used for
processor thermal solution design targets. TDP is not the maximum power that the processor can
dissipate. TDP is measured at maximum TCASE.1
. The thermal profile must be adhered to to ensure
Intel’s reliability requirements are met. Note: Different processors SKU’s have different TDP’s. At the
time of this writing, Intel® Xeon® processors for 2 socket servers (5600 series) are available with a
TDP specification from 40W up to 130W depending on the particular SKU1

AMD Opteron* processors also have a TDP specification. According to AMD documentation2
their TDP
specification is as follows:
“TDP. Thermal Design Power. The thermal design power is the maximum power a processor can draw
for a thermally significant period while running commercially useful software. The constraining
conditions for TDP are specified in the notes in the thermal and power tables.”
Notes:
- TDP is measured under the conditions of all cores operating at CPU COF, Tcase Max, and VDD at
the voltage requested by the processor. TDP includes all power dissipated on-die from VDD,
VDDNB, VDDIO, VLDT, VTT and VDDA.
- The processor thermal solution should be designed to accommodate thermal design power (TDP) at
Tcase,max.TDP is not the maximum power of the processor.
http://www.intel.com/content/dam/doc/wh ... -paper.pdf