C2D 6420 Tcase higher than Tjunction

[Oatz]

I was going to replace my stock Intel heatsink as well as start overclocking my new 6420, but first I wanted to make sure I had an accurate way of gathering temperature information.

There are several temperature programs out there and I have tried them all out. The results seem to match up between all the programs, but the one thing that still has me confused is the fact that my Tjunction temp is lower than my Tcase temp.

From what I have gathered, Tjunction is suppose to be higher than Tcase by 15C +/- 3C.

I have been using TAT, SpeedFan 4.32, CoreTemp .95 and the Nvidia monitor to look at my temperatures.

TAT, CoreTemp and SpeedFan (Core0 and Core1) are suppose to be the Tjunction temperatures.

The nTune monitor, SpeedFan (CPU), and the bios temp should all be the Tcase temperature.

Idle: Tcase temp is ~41C and Tjunction is ~33C.
Idle
Load: Tcase temp is ~62C and Tjunction is ~56C
Load

I have seen some other posts with people having the same issue on other forums as I and the answer seems to be to simply change the offset of the Tjunction reading in SpeedFan so that it displays correctly. This doesn't seem like a fix to me though, because I still know that the temperature is not reading correctly. Plus, doing this seems like you are just making a best guess as to how much the temp is off.

Does anyone else have a similar issue with the 6420? And can anyone explain which temp I really should look at in regards to overclocking?

Thanks 🙂


C2D e6420 Stock
EVGA 680i

 

[renozi]

that's really weird. I've seen other with tcase higher than tjunction at idle, but tjunction higher than tcase at load. that's also weird. It's true that tjunction should be ~15C higher than tcase, though.
Perhaps something wrong with the onboard sensor on the motherboard?

 

[aigomorla]

okey its IMPOSSIBLE to take the temp at TJunction unless you bore the side of the IHS, and leave a temp probe inside. This has been widely discussed.

Also, the more important temp to be aware of, and possibly the most accurate, is your TAT/CoreTemp program reading. More people prefer coretemp over TAT. This program messures the temperature on/near the cache area of the DIE. Hence this will tell you with near accuracy what your relative die temperatures are. This also displays the thermal shutdown for the temp on the core.

In a C2D case i believe coretemp 85C is where the comp will shut off. The absolute safe limit for C2D's was 70C. This is where the most consensus lies.

So as long as you dont spike above 70 too much your temps are fine.

Lastly, some engineers estimated, that every 10C you bring your CPU temps, you effectively double your processors life. But how fast technology is moving, i highly doubt a lot of people will keep their processors longer then 3 yrs. So this wouldnt really apply to the majority.