Sorry it took me so long to respond.
In Hardware Monitor, "Package" is following the highest Core temperature, while "CPUTIN" is CPU temperature. In SpeedFan, "Temperature 2 offset"
is CPU temperature. As I mentioned in my first answer, I use SpeedFan because I can calibrate all five temperatures (the single CPU temperature and the 4 individual Core temperatures). Although BIOS updates often include undocumented fixes, I wouldn't depend upon an update to correct inaccurate CPU temperature.
When Intel conducts thermal testing in their labs, (which is detailed in their White Papers), it's under tightly controlled environmental conditions (22.0C / 71.6F). A groove is cut into the Integrated Heat Spreader (IHS) where a thermocouple is embedded in the center, then the stock cooler is attached, and a steady-state 100% workload is run. This in turn yields a steady temperature after thermal saturation is reached, which requires less than 10 minutes.
Since the thermocouple is highly accurate, Intel's Thermal Specification, (shown as "Tcase"), is expressed to the tenth of a degree, which for the i5 3570K, is 67.4C. As the thermocouple is used for lab testing only, the single Analog Thermal Diode (positioned in the center of the processor die within the lower layers of the substrate material) is used instead to "emulate" a laboratory thermocouple. The accuracy of the emulation (CPU temperature) is determined by the "look-up" tables in BIOS, which is all too often mis-coded for many socket 775, 1155, 1366 and 2011 processor variants.
As neither the single Analog Thermal Diode (CPU temperature) or the individual Digital Thermal Sensor (DTS) for each of the 4 Cores is not as accurate as a thermocouple, the specification for Tjunction Max is expressed as a whole number, rather than to the tenth of a degree, which for the i5 3570K, is 105C (shutdown temperature).
Observing Intel's 67.4C Tcase specification, we simply add 5C for the thermal gradient offset (shown in Intel's White Papers) to convert from Tcase (CPU temperature) to Tjunction (Core temperature), then we have 72.4C as an equivalent Core temperature to Intel's lab tests. If your Ambient temperature was below or above 22C when you tested your rig, then remember to add or subtract the difference to correct your test results for 22C Standard Ambient.
Ambient = 22C
Tcase Spec (CPU temp) 67.4C
Gradient Offset +5C
Tjunction (Core temp) = 72.4C
Tj Max Spec (Shutdown temp) 105C
When we consider overclocking, all experienced overclockers know that a cooler processor is a more stable processor. When corrected to 22C Ambient after running Prime95 Small FFT's, I can never, in good conscience, recommend Core temperatures higher than 75 ish. Excessive heat kills electronics. Personally, I believe that 80C and up is just too hot for sustained operation and longevity for CPU's, as well as GPU's.
Some additional guidelines for the benefit of others who may read this:
All Core 2 and Core i generation processors - do not exceed 75C.
1st generation Core 2 processors 65 nanometer - do not exceed 1.5 Vcore.
2nd generation Core 2 processors 45 nanometer - do not exceed 1.4 Vcore.
1st generation Core i processors 45 nanometer - do not exceed 1.4 Vcore
2nd generation Core i processors 32 nanometer - do not exceed 1.35 Vcore.
3rd generation Core i processors 22 nanometer - do not exceed 1.3 Vcore.
The bottom line is that although your CPU temperature is inaccurate, and would be 5C below "average" Core temperature if it had the correct look-up tables in BIOS, your Core temperatures are normal for "high-end" air cooling at stock clock. You won't see higher temperatures until you overclock enough to require a higher Core voltage.
For example, Intel's Thermal Specification for my i7 2700K is 72.6C, which would make my "do not exceed" Core temperature 77.6c. As you can see in my signature below, I've pushed my Vcore to the limit and my Core temperatures about as high as I care to go, which gives me a stable 4.8 Ghz overclock for a 12 hour run of Prime95 Small FFT's. It's all about understanding the specifications.
Hope this provides additional clarification,
Comp