Per the Guide:
"Test:
Run Prime95 v26.6 Small FFT's for 10 minutes, then use your thermometer to measure Ambient. Use Core Temp to measure your Core temperatures.
Results:
If reported Core temperatures exceed 80C, you should reduce Vcore and clock speed and / or improve cooling. Core temperatures in the mid 70's are safe.
Note: Early Legacy 65 nanometer Core 2 variants with stepping revision B2 and B3 have lower TjMax specifications than other processors. Use CPU-Z to view your stepping revision. For these variants, Core temperatures in the mid 60's are safe.
Intel’s specification for Digital Thermal Sensor (DTS) accuracy is +/- 5C. This means deviations between the highest and lowest Cores may be 10C, so "Average" Core temperature is often more realistic.
On processors with more than 2 Cores, the inner Cores run warmer because they’re insulated by the outer Cores. Here’s the physical layout in 2nd, 3rd and 4th Generation Quad Core processors, and an example of how it typically affects Core temperatures:
IGPU = Not in use (PCIE graphics card in use)
Core #0 = 75C (insulated by IGPU and Core #1)
Core #1 = 78C (insulated by Core #0 and #2)
Core #2 = 76C (insulated by Core #1 and #3)
Core #3 = 71C (insulated by Core #2 only)
Core Average = 75C.
Note: When viewing your temperatures in Core Temp, values which reach 81C or higher will change from black to amber, which indicates caution.
Normalize your results to Standard Ambient and record the values for future reference."