The effective thermal conductivity
What had already become apparent with thermal resistance does not change here either. Anyone who still believes that thermal conductivity is a constant value is very much mistaken. But I have already explained this at length in the basic article. If you have Rth, you don’t actually need λeff, i.e. the effective thermal conductivity. And the result? The slightly more fluid Paste X is hardly worse than the Thermalright TF8. For the relevant thicknesses below 100 µm, both are almost on a par, and below 50 µm anyway. This is where the Kryonaut catches up significantly.
Of course, the whole thing is also shown again as a bar chart for the four most important layer thicknesses:
Apart from the fact that I also have the temperatures of the heater and the water, which are of no use to us because they either adapt to the resistances or always remain constant, I have my measurement setup with temperature sensors 1 to 6 (see diagram on page 2). These values can also be used to make some very interesting considerations.
GPU emulation
Let us first take the values of T3 and T4, which show us the two temperatures at the respective contact surfaces between which the paste is located. These curves are no longer completely linear, as the interface resistance also changes slightly. And we no longer calculate with 6 points, but only with 2 absolute values for the temperature difference instead of a gradient as withTTim, whereby the sample temperature remains constant. And what is the point of all this? The behavior is similar to that of a graphics card, which has to manage without an IHS and where the delta is usually measured between the substrate and the water temperature. This can be projected quite well, because I test the temperature difference on the two surfaces between which the paste is located. And here, too, you can see that there is less than 1 degree difference below around 100 µm.
CPU emulation
If we normalize the values for the heater and take the gradient to T3 into account, then we already have sufficient thermal resistance in the reference block made of copper to T3 to simulate the CPU temperature and its differences with different pastes in comparison with each other and depending on the layer thickness of the paste. It is precisely this variable evaluation that no test on a CPU can offer, because it is always individually different and therefore not really reproducible. But the TIMA5 test does. Here, too, both pastes are very close to each other.
20 Antworten
Kommentar
Lade neue Kommentare
Urgestein
Urgestein
1
Urgestein
1
Urgestein
Veteran
1
Veteran
Veteran
1
Veteran
Urgestein
Veteran
Urgestein
Veteran
Veteran
1
Veteran
Alle Kommentare lesen unter igor´sLAB Community →