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Incoherent · 12-10-2003, 06:05 PM

I have continued the analysis, I have come to the (unexpected) conclusion that my CPU diode is in fact telling the truth, relative to the water sensor. The (I have started calling it) "flux block" readings are 1.925°C out. This conclusion is reached by looking at the Calculated power vs T graph, normalised to water temperature and extrapolating down to zero CPU power output. Here are both unnormalised and normalised

The CPU diode temperature crosses 0W very close to average water temperature (15.6°C), the 0W temp for T1 and T2 is 1.925°C higher, in the normalised chart I have corrected them.
This check of the measurement system is open to debate but I believe it is valid.
Trusting this means a lot of other things fall into place. For example I have a number for the CPU diode/TIM joint, based on over 500 data points, statistically significant, of:
0.063C/W
and for the WB+TIM
0.162C/W
These are unexpectedly low perhaps and I am uncomfortable in stating them as fact, it is sure to draw fire. But, I am only working the numbers, and that is what the numbers say. (Les, if you can be arsed, I would welcome some cross checks)
Secondary path losses I am having trouble quantifying, they appear to be an odd function of water temperature and W, getting higher (actually might be lower

) at both low and high W and dipping in the middle. I cannot figure out a mechanism for that behaviour. I think I might have to remeasure with more controlled (although varying) water temps in order to track that mechanism through the noise. I don't think I have all the data points needed.

Be gentle

Incoherent

12-10-2003, 06:05 PM	#72
Incoherent Cooling Savant Join Date: Sep 2003 Location: Vallentuna, Sweden Posts: 410	I have continued the analysis, I have come to the (unexpected) conclusion that my CPU diode is in fact telling the truth, relative to the water sensor. The (I have started calling it) "flux block" readings are 1.925°C out. This conclusion is reached by looking at the Calculated power vs T graph, normalised to water temperature and extrapolating down to zero CPU power output. Here are both unnormalised and normalised The CPU diode temperature crosses 0W very close to average water temperature (15.6°C), the 0W temp for T1 and T2 is 1.925°C higher, in the normalised chart I have corrected them. This check of the measurement system is open to debate but I believe it is valid. Trusting this means a lot of other things fall into place. For example I have a number for the CPU diode/TIM joint, based on over 500 data points, statistically significant, of: 0.063C/W and for the WB+TIM 0.162C/W These are unexpectedly low perhaps and I am uncomfortable in stating them as fact, it is sure to draw fire. But, I am only working the numbers, and that is what the numbers say. (Les, if you can be arsed, I would welcome some cross checks) Secondary path losses I am having trouble quantifying, they appear to be an odd function of water temperature and W, getting higher (actually might be lower ) at both low and high W and dipping in the middle. I cannot figure out a mechanism for that behaviour. I think I might have to remeasure with more controlled (although varying) water temps in order to track that mechanism through the noise. I don't think I have all the data points needed. Be gentle Incoherent Last edited by Incoherent; 12-10-2003 at 08:58 PM.