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JHeij2
Beginner
1,368 Views

Two cores too hot / i7-870

Hi!

I'm testing an old i7-870. Intel Stock cooler, new thermal paste, correctly mounted.

At idle, all four cores show almost the same temp, 35-40°C

At max load using Prime95, core 1 and especially core 3 stands out with high core temps, and rises fast to that level.

Core temps: 69, 90, 71, 92 celcius

Frequencies: about 3.0 GHz for all cores

Why such big difference in temps ?

Is it reliable to use with high load for hours of gaming etc?

Can I trust that the CPUs internal thermal protection mechanism throttles the cores by lowering the frequency for one or more cores if nessecary ?

At which core temp does throttling occur?

Regards

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4 Replies
n_scott_pearson
Super User Retired Employee
135 Views

Seeing these odd temperatures is making me think that the heatsink is not properly attached to the processor; that one side is not as effectively attached as the other I would remove, clean and then reinstall

Throttling starts at the Maximum Junction Temperature, Tjmax, which is typically within the vicinity of 100c but can vary from one individual processor to another. Some Intel and third-party test tools can display the actual Tjmax temperature.

Hope this helps,

...S

JHeij2
Beginner
135 Views

Totally agree with you. However, I have already installed the cooler twice (cleaned and new thermal paste). Same high temps.

The cooler is a simple stock cooler. It has a flat surface, as well as the IHS. Thermal paste looks well spreaded. This cooler works good on CPUs.

So, next thought, is it possible that some area of the IHS is not effectively attached to the CPU?

According to what I have read, the i7-870 IHS is soldered, not just thermal paste.

Or do the core temperature sensors really give correct temperature?

Or is it possible that this is a bad manufactured CPU from the beginning and nothing to do but just use it and not care about the temps?

n_scott_pearson
Super User Retired Employee
135 Views

With solder-based manufacturing, I rather doubt there's a heat transfer issue. I am more inclined to think it's a broken sensor.

I would say run it and ignore temps. Presume it's a bad sensor. If the processor eventually fails, well, upgrade then.

...S

JHeij2
Beginner
135 Views

Thanks for your support!

The most reasonable ought to be a bad sensor, as you say,

Today I installed a BeQuiet! Pure Rock Slim, and got a little bit lower temperatures, but it still differs a lot between cores.

Core temps running Prime95

69, 90, 71, 92 (Stock cooler)

66, 76, 68, 82 (Pure Rock Slim)

I'll run it like this.

Thanks again!

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