Realtemp uses a TJ MAX of 95 vs 100 for core temp.
Your temps are figured out by the software asking the cpu how far are you from your TJ MAX. The cpu gives it a number and it just does the math
So if the cpu says i am 45 away
Core Temp. 100 - 45 = 55
Real Temp. 95 - 45 = 50
Intel did not list a TJ max for the cpu. Different users will tell you to use different software.
If you want to know more about Core2 temps, there is a guide linked in my sig. Check it out.http://www.tomshardware.com/forum/221745-29-core-quad-temperature-guide