[SOLVED] Insanely high idle temps - genuine overheating or likely sensor error?

Barney Willis

Jul 30, 2013
Hi all,

I recently noticed a sudden drop in performance in my PC and eventually traced it to extremely high CPU temps (over 100C at idle :O) A few months ago they idled in the 50s. I have cleaned the heat sink of dust but the temps persist and am now nervous to turn it on in case it does damage.

I have ordered new thermal paste but I was wondering if these temps can be explained through thermal paste wear and tear alone. Maybe a sensor error or is my CPU on the way out? These temps seemed a bit extreme so I was wondering if there are other explanations other than the fact the paste hasn't been changed in ages.

Processor is an i5 3570k on stock cooler. Using HWmonitor and MSI afterburner for temps. Ambient temp is about 20 degrees.

Much obliged :)
If any cooler is working and installed properly, you should see about 10-15c. over ambient.
If you are looking at a stock intel cooler, it has likely come loose.
Another possibility is that the case ventilation is not supplying sufficient fresh air to let the cooler do it's job.
Take the case covers off and direct a house fan at the innards. If this helps, you have a case cooling problem.

----------------how to mount the stock Intel cooler--------------

The stock Intel cooler can be tricky to install.
A poor installation will result in higher cpu temperatures.
If properly mounted, you should expect temperatures at idle to be 10-15c. over ambient.

To mount the Intel stock cooler properly, place the motherboard on top of the foam or cardboard backing that was packed with the motherboard.
The stock cooler will come with paste pre applied, it looks like three grey strips.
The 4 push pins should come in the proper position for installation, that is with the pins rotated in the opposite direction of the arrow,(clockwise)
and pulled up as far as they can go.
Take the time to play with the pushpin mechanism until you know how they work.

Orient the 4 pins so that they are exactly over the motherboard holes.
If one is out of place, you will damage the pins which are delicate.
Push down on a DIAGONAL pair of pins at the same time. Then the other pair.

When you push down on the top black pins, it expands the white plastic pins to fix the cooler in place.

If you do them one at a time, you will not get the cooler on straight.
Lastly, look at the back of the motherboard to verify that all 4 pins are equally through the motherboard, and that the cooler is on firmly.
This last step must be done, which is why the motherboard should be out of the case to do the job. Or you need a case with a opening that lets you see the pins.
It is possible to mount the cooler with the motherboard mounted in the case, but you can then never be certain that the push pins are inserted properly
unless you can verify that the pins are through the motherboard and locked.

If you should need to remove the cooler, turn the pins counter clockwise to unlock them.
You will need to clean off the old paste and reapply new if you ever take the cooler off.
Clean off old paste with alcohol and a lint free paper like a coffee filter.