Thumper

The question.

Is it safe to run a Core 2 Duo at up to 85c as measured by the Thermal Analysis Tool from Intel?

To answer this question, we need to determine if the temp of the core (which is measured by TAT) is different than the temp of the center of the IHS, as this is where Intel gives us the max safe threshold.


I got everything set up and ran some quick tests. Unfortunatly the sensor wire kept the heatsink from sitting flush so I could not run a load test, but did take measurements with idle and 50% on one core. I tried placing the sensor 2 different ways neither had any impact on temps or seating of the heatsink.

Here are the results;

This is proof of the placement of a thermal sensor on my IHS, positioned to read the center.

Thermal Probe Placement


Measurement of the core through TAT at idle in the destop:

Core Temp Idle

As you can see,Core 1 reads 51c and Core 2 reads 45c. I beleive the difference in temps is due to the seating of the heatsink, without it the two cores are usually no more than 3c off each other.

Now, here is what the thermal probe reads at the same time as the screenshot was taken.

Thermal Probe Idle

It varied from 51-54c over a minute long period.


Here is the TAT reading with 1 Core at 100% (50% CPU load)

Core Temp 50%

It clearly shows Core 1 at 57c and Core 2 at 54c. These readings bounced slightly going as high as 60c/56c.


Now, here is the thermal probe reading for the same time.

Thermal Probe 50%

It clearly shows 59c, it also varied slightly over a minute period, going as high as 63c.



Personally, this is fairly conclusive evidence that there is very little difference between the temps reported by TAT and those seen at the center of the IHS. In fact there was very little difference between the temps reported by TAT, and by PC Probe, within 3c of each other usually.

Since the recomended guidelines for a Core 2 Duo stated by Intel, and measured at the center of the IHS are approx 60c, and the temps reported in the cores are almost identical to those found on the IHS center, there is no support for safe operation of a Core 2 Duo over 60c, regardless of the program used to measure the temp.

It should also be noted, that the 60c mark is listed by Intel for a CPU being operated at stock settings. For an oveclocked Core 2 Duo, within Intel voltage specs, 55c is the maximum I would recomend for 24/7 operation.

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Fishie36

Isn't that the kind of sensor that always comes with a warning about not applying pressure to the sensor?

ckp64

Excellent work!
Good thing my C2D hasn't come even close to 60C...yet.
But I am nearing 55C .

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mcb

Thank. You.

You don't know how long I've been looking for this kind of straight forward post.

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You are a godsend! Well maybe not really.... but hey, someone give the man some sort of consolidation prize! :P

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Highly-Annoyed

Good work Thumper!

So, in general we can conclude that Core 2 Duo / Extreme is best kept under 60°C when both cores are fully loaded, as reported by TAT, or other software like Speedfan. This is useful information. I've seen plenty of folks running their C2Ds at higher than 60°C though... What happens after 60°C? Does the CPU throttle? I would of guessed it would..?

Fortunately my C2D doesn't break 40°C fully loaded, but it's not o/c'ed much
and is still using stock voltage... Still, some good headroom for future o/c'ing .

Good thread! REP for you!

Highly-Annoyed

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The_Manual

Stealing my post from the other thread

Not all parts of this quote are related to this thread. I am glad that you have proved to yourself and the membership that the thermal level of this chip must not exceed 60.1C for safety reasons. As I don't really want a lot of people with broken chips after a few months

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Radeon915

Ah I was waiting for this for so long.. Thanks a lot!
I'm at 58C so luckily still safe

Rep+!

Thumper

No, it's the kind of sensor that was specificly made to be mounted between the IHS and the heatsink. The Gatewatch comes with 4 sensors, 1 for the CPU, 1 for the VGA, 1 for the ambient Case, and 1 for a Hard drive.


Throttling is different. Throttling usually occurs to avoid immediate, catastrophic failure. Sometimes it can be much higher than the safe temp. After 60c the heat will increase the amount of damage caused by electromigration, dramatically shortening the life of the CPU. Intel warrenties the CPUs for 3 years if they are kept within the listed voltage and thermal guidlines and at stock settings. Realistically, they will last much longer than that otherwise they would lose money replacing dead chips. If one plans to replace a CPU within 18 months, voltage and thermal guidelines may not concern them as much, and spikes into the higher temps are different than constant, steady trips there. Hitting 65c for 2 minutes once will not shave years or months off the CPU, running at 65c 24/7 will.

Again, those guidlines are for stock CPUs, when we overclock, even without increaseing voltage over the listed spec, there is greater strain which can cause increased damage even within the listed thermal guideline. Which is why 55c is a more acceptable guidline for overclocked CPUs.




Your post in the other thread is partly what prompted me to do this, as I heard what you said, and saw resistence to accept it even though it was fully based in logic. You know what they say, a picture is worth a thousand words. I figured some real world tests would back up what you had already stated.


Nor do i...

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