Location of P4's thermal diode
 

Finally - I had seen this ages ago, but had forgotten where the document was.

Was reading through Roscal's micro-channel document and he had a link to it:

http://developer.intel.com/update/de...ch/it04021.pdf

The P4's thermal diode is located in the corner in the absolute coolest possible position of the CPU, hence effectively reducing much of the validity of using P4's for comparing waterblock performance, which is an experimental conclusion that I came to long ago.

Would love to see where AMD have put their thermal diode, but given the really low temperatures that AthlonXP CPU's report when reading the thermal diode, I suspect that they too have done a similar thing.

Man, I feel so happy to find that document again.

I have read that Intel has more than one thermal diode; an external one in the cool spot for monitoring temps with motherboard and a second diode in a hotter location used for the actual clock throttling. This second diode is not externally accessible (no pin). I don't recall the exact source of that info (Nevin or Bill?)