The only way you are going to get some reasonably accurate reported temperatues is if you take the time to check and adjust your calibration. On the XtremeSystems forum, rge did some extensive testing with both an IR thermometer as well as mounting a calibrated thermocouple into the IHS lid over top of his processor. The calibration procedure involves running your CPU at a fixed MHz and at a reduced core voltage. This helps equalize the heat ouput of a wide range of CPUs so the difference in reported temperature between a Q6600 G0, an E8400 C0 and an E2160 with 1MB of cache should only be +/- 1C at these settings with the E8400 representing the mid point.
You need to set your CPU to default MHz for this test. The front side bus should be set to 266 MHz for 65 nm processors and to 333 MHz for the newer 45 nm processors. Core voltage needs to be set to 1.10 volts as reported by CPU-Z. The CPU multiplier needs to be set to 6.0 at idle or 12.0 for Core i7. You can either enter these values manually into your bios or you can also enable EIST, Enhanced Intel Speed Step, which is designed to drop your CPU close to these values automatically at idle. Not all motherboards properly support EIST so it's best to check using CPU-Z to confirm these values.
Open your computer case and compare your reported idle temperatures to your room temperature near your case or to your water temperature if you are water cooled. Based on the type of CPU cooling you are using, Core 2 based CPUs should be seeing reported temperatures similar to what rge saw during his testing.
COOLING...............................IDLE DEGREES ABOVE AMBIENT
High end water...............................6C above ambient
High end air (true push/pull) ........6-7C
High end air (1fan).........................7C
Mid air (zalman 9500)....................8-9C depending on fan rpm
Intel stock cooler...........................10-11C
If your reported temperature is too low then you will need to go into the RealTemp Settings window and use a positive calibration factor to increase your reported temperature. If your CPU is reading too high, you will need to use a negative calibration factor. On a multi-core processor during this test, you should have equal temperatures for all of your cores. Though this calibration test is done when your processor is idle, the calibration settings entered will improve the accuracy of your reported tempertures from idle to TJMax. Return your computer to your normal MHz and core voltage settings and if you need to, you can make some further minor adjustments to equalize your core temperatures at idle. You shouldn't need to make any major adjustments at this point.
Based on Intel's specs and during initial testing, the Core i7 CPUs seem to be more efficient and create less heat at idle compared to previous Core 2 Quad processors. Your results will likely be a couple of degrees less than the numbers listed in this chart depending on how your bios and Windows power management options are set.