Cooling experts out there, some help please

[Mark Hahn]

> What I am interested in a chart that define maximum
> internal die temp / Die surface temp / Heat sink temp
> for intel processors.

well, if you look at a PIII datasheet, it indicates the max
Tjunction is around 80C (lower for higher clocks, interestingly),
fan intake are <= 45C.  I'd guess that the Tjunction-offset
(diff between Tj and the internal diode reading) is a 
conservative approximation of the deltaT between inner and 
outer surface.  it's given as 4C.  so at the working surface
of the heatsink, you need to be at, say, 76C.

HS's seem to be characterized by vendors in thermal resistance, 
deltaT per watt.  so a random Thermaltake unit lists .64C/W,
which given, say, 24W for a PIII/733, means -16C cooler ambient,
or a max of 60C in the case.

as another example, P4/1700 specs say 64W thermal design power
max Tcase 76C, Tambient 30C or so.  oddly, it also says 
50.2W of 1.7V power (85W, not 76!)

> The chart could also specify different heatsink
> material types CU,Al...

design makes at least as much difference as material.