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Difference between tj and tc temp?

T

the tin tub

n00b
Joined
Dec 15, 2009
Messages
43
Hi guys.

I recently got my hands on a Venomous 120 CPU cooler for my Q6600 as a stop-gap fix to gain some speed until I'm ready for a system overhaul. I popped it in and OC'ed from stock 2.4ghz to 3.2ghz.

After doing some reading I was pointed towards Realtemp as a good way to get an accurate reading on my CPU's temp. I loaded that up while running a torture test in Prime95 and found that it reports about 65 degrees after a 10 hour test at 100% load.

This sounded high to me so I did some more reading. Since Realtemp uses "tj" temps, (which is inside the CPU if I understand things correctly) and most other temp readers use "tc" temps, which are on the top of the CPU, the high temp is actually well within normal and I should not be worried.

Is this accurate? Is a tj temp of 65 degrees OK after 10 hours of 100% load? I'm new to OC'ing so I want to learn as much as I can :)

Thanks!
 
Cut and pasted from here. Which seems to be cut and pasted form tomshardware.

"Heat originates within the Cores, and is hottest where the dual Tjunction sensors are located. Heat is then dissipated throughout the CPU die to the socket and motherboard, and to the Integrated Heat Spreader, where the single Tcase sensor is located between the Cores, and the temperature is ~ 15c cooler. Heat is then transferred to the CPU cooler, and finally to air inside the computer case. All 3 C2D temperatures are then determined by computer case cooling efficiency and Ambient temperature. Regardless of Load, Tjunction is always ~ 15c higher than Tcase, and Tcase is always higher than Ambient."

Clfifs

Tj temps are higher because they are taken closer to the cores and the tc temps are taking further away allowing heat to dissapate.
 
Right, OK, thats what I thought. So its a 65 degree tj temp pretty reasonable after 10 hours at 100% load?
 
/Sigh

We at hardocp where the prioneers of determining what was going on in an Intel Digital Temperature Sensor. Our member Unclewebb (who still drops by occasionaly) wrote RealTemp.

Your cpu is good until about 100C (core temp) where it will put out an "I am getting hot" signal to the motherboard to spin the fans up to 100% speed and start reducing the mulitplier and voltage to reduce heat. This is TjMax. And since it is not really a max it is misnamed. TjHot would be more descriptive. At some temp above that which Intel has not made public but based on other cpus a good guess is 10-20C above the 100C number the cpu will shut down to save itself.

In Realtemp, coretemp etc. look a the value of "Distance to TjMax" this tells you in deg C how many deg C of headroom you have before the CPU thinks it is too hot.

Forget Tc (Tcase) it requires that a thermocouple probe be machined into the heat spreader of the CPU and it is not something any of us can do or use in normal situations. Keep the core temp as reported by Realtemp etc. below 85C , which gives a 15 C margin and you are good.

http://hardforum.com/showpost.php?p=1031827510&postcount=31
 
Thanks again Bill.

My Q6600 is running at a tj temp of about 63 degrees at 100% load. Pretty happy with that!
 
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