| CPU is at 23C? Are we looking at the same image? The CPU is the heat generator there, and is in contact with metallic regions around 60C (the red ring, if you compare to the real picture and follow the metallic bevels), where heat conductivity abruptly drops, which is what I've been talking about from the beginning. Since the heat is generated by the CPU and flows to the metal casing and to the PCB, the CPU can't be lower than 60C. I agree that the reading for the inner region of the metal casing (which is not the CPU) must be off, and it's probably because the emission intensity there isn't strong enough and the camera software is mixing the emission and reflection when inferring the temperature (which gives physically incorrect results because the spectrum won't obey Planck's law, but the error depends on how different the temperatures are, and gets much stronger as they drift apart) rather than doing something like a "dark frame" subtraction (which is doable in principle). Accuracy concerns aside, though, everything we see there (when you consider the physical context) supports the fact that the metal casing helps spreading the heat (which is obvious, it's a material which high heat conductivity, and there wouldn't be any need to put it there otherwise). Even the 60C reading must be off by some for the same reason (given the regions appearing at around 70C), of course, but I assume OP doesn't care about that level of accuracy. |
I disagree that the thermal image provides evidence of those truths
Does the image prove the CPU has a low temperature? No, the image reports the temperature inaccurately. Does the image prove the package has no hotspots? No, it wouldn't show hotspots if they were there. Does the fact the PCB gets hot tell us much? Not really, you'd expect heat to conduct from the package and balls to the PCB no matter what the package was made from.