Hexa, I'm going through a similar exercise at the moment, and was wondering what your TJMax is set to in RealTemp? It seems the default setting is 98C but on my 2500k that was telling me idle temps were ~10C lower than ambient temps in my room. I don't think that is possible. Based on my reading around the net and trial & error I have lowered the TJMax value to 90C, and that seems to be more accurate.
With ambient in my room at 26.7C, my PC has been running Prime95 for nearly 6 hours now, with frequency at 47X 100MHz (4700 in CPU-Z), and the CPU temps seem to be peaking around 66C. Although I was hoping to keep around 60C, I have had to up voltage a few times to keep it stable, otherwise Prime95 was throwing Rounding Errors. Just to be on the safe side, I have set a thermal alarm in RealTemp at 72C, so if this temperature is reached it will shut the system down. There are instructions on the RealTemp web site for how to do this.
Why 72C? Because Intel states the TCase limit for the 2500K is 72.6C Intel-Core-i5-2500K-Processor-reference page.
I don't exactly know what TCase represents, I assume thermocouple temps taken at the outer case of the CPU, which likely means internal core temperature may be 10+C higher. There is a lot of different opinions on this, but I prefer to err on the safe side, so I'm aiming for lowest thermal load as I OC my PC. It would seem 4.7GHz is as far as my setup will go at safe temps, assuming it runs overnight tonight and doesn't reach the thermal alarm I have set.Edited by PhilC2001 - 2/19/12 at 7:48pm