Fatal1ty Z170 ITX/ac Temps

You never had a temperature discrepancy issue in the first place. BTW, what are you using to check CPU temperatures, the Corsair Link software?

That is known to be rather buggy software. I would get a second opinion with something like HWiNFO, which reads CPU temperatures from the CPU. Of course if you believe sub-room air temperatures are impossible for PC components, then you'll think you still have problems.

When you ran the two stress tests, if you did not duplicate the conditions with the fan speeds on the CPU cooler, then you can't compare the resulting temperatures.

Your first post said no OC, and now you have an OC to 4.6GHz. If you are comparing the CPU temperatures between no OC and your current OC, that again is comparing two different situations.

You should check what Intel considers the maximum temperature for these CPUs. As long as you're under that and as long as the system is stable under stress testing, you should be fine. 40 minutes of stress testing should be enough for the temperatures to plateau, but I wouldn't consider it enough to prove stability. What are you using for stress testing by the way?

parsec wrote: My theory about this is certain materials like metal seem to retain less heat energy than other materials. Liquids like water can also have this affect. Actually these materials are absorbing heat from other objects much more quickly and to a greater degree than others, and create the affect that they are cooler. Have you ever touched metal that seemed cooler than wood or plastic that is right next to it?

It's not just your theory, it's basic physics: Different materials have different heat capacities and thermal conductivities. A high heat capacity means that the material can store large amounts of heat energy, which in turn means that in order to change the material's temperature by e.g. 1 C, you need more heat energy than you would with a material that has a low heat capacity. A material with a high thermal conductivity will be able to either absorb or donate thermal energy more quickly than a material with a low thermal conductivity.

In the example you give above and assuming we're talking about objects that have been in the same ambient temperature for enough time, the actual temperature of those objects will be exactly the same. The reason some materials feel cooler than others is because of the differences in heat capacities and thermal conductivies. Some materials will absorb heat as fast as your skin can donate it, and need a lot of it to warm up, which can cool your hand's temperature quite efficiently. On the other hand some materials will absorb heat slowly, allowing your bloodcirculation to better keep up with the heat transfer and leading to your hand being cooled less, even if you need to hold on for longer to make the object body temperature. Note that what you are actually sensing is not the temperature of the object you're grabbing, it's the temperature change of your hand. Regardless of how fast heat is transferred from one object to another, the lower and higher temperature limits (ambient and body temperature, respectively) in this example are the same for all materials.

Imagine a large metal heat sink, or one that contains liquid like an AIO cooler the OP is using. These devices are designed to absorb heat that is then absorbed by cooler air or water. The heat sink will remove heat from the CPU faster than it is being created in the CPU. If it didn't, the heat sink would not do its job. If heat is being absorbed away from an object (with a temperature sensor) faster than heat is being created or absorbed into the object, won't that object be cooler than its surroundings?

Depends on what you cool it with. If you use ambient air to cool the CPU, then ambient temperature is the lower limit to the CPUs temperature. If you use a liquid cooler where the liquid is only cooled using ambient air - meaning the liquid is just an efficient way of transporting heat from the CPU to the radiator - then the lower limit is again the ambient temperature. This is because heat only flows one way, from higher temperature to lower, and once the CPU reaches the temperature of whatever is used to cool it, heat will no longer be transferred from it (on a macroscopic scale) no matter how efficient the cooling system is. Furthermore, since having the computer on at all makes the CPU a heat source, it should in practice always be slightly above room temperature if ambient cooling is used, since no CPU cooling is ideal. Sub-ambient CPU temperatures can only be achieved if you have sub-ambient cooling.

IMO, the notion that every object in a space (room) is at the same temperature as the air in a room at all times is false. We take for granted that every object in a room is the same temperature as the "room temperature". Get an infrared thermometer and check the temperature of any object or surface in a room, they can be quite different.

This is true, but mostly because the air temperature in the room is not homogeneous and there are often both heat sinks and sources in a room: Windows, electronics, draft coming for other rooms etc. all of which affect both how air is circulated in a room and what sort of temperature gradients there are. But while you might see a difference in temperatures when you compare a plant on a window sill or the remote next to your stereo amplifier, it's not really a bad approximation to assume objects to be "room temperature". Unless the room is very drafty and has large temperature gradients (such as sub-zero temperature air flowing in through windows), one shouldn't see 15 C CPU temperatures if the "room temperature" is 20 C.

Ok, thanks.

Hmm, is there a way to calibrate it? Or am I just gonna have to live with it?

I was thinking about taking the motherboard and getting a replacement, but there's no guarantee it won't have the same issue.