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Originally Posted by pHaestus
Any estimate on how much performance difference is due to a few little tweaks and how much is due to silver?
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For me, given a ~100W CPU heat load, I sorta-kinda honed in on a 0.7C improvement with the SS over the standard copper based block.
Of that:
Tied to cup porting and jet tweakage:
~0.1C as a result of cup porting giving lower pressure drop giving slightly higher flow rates
~0.2C as a result of the jet tweakage
Both of the above could be applied to the copper block by anyone who cared to, but it's very fiddly work which I was doing by hand. Somewhat at a cross-over point of if it were better to do it via the NC, or by hand.
Tied to the metal and base-plate tweaks:
~0.2C tied directly to the use of silver's higher thermal conductance
~0.2C tied to base-plate thickness tweakage to match the silver's higher thermal conductance
So basically ~0.4C due to the silver, but only by modifying the design to take advantage of the silver, as opposed to the ~0.2C that would've been gained by just using silver without changing the design.
Les, I have no real strong working models for what goes on in a Cascade. It is still somewhat of a mystery, mostly because at times when apparant theory said that things should be getting worse, they were actually getting better. I have enough of an understanding through emperical data on how to tweak it to best effect, and a rudimentary set of hypotheses of why, when tweaking one aspect, a certain result comes about.
There isn't really enough room in a Cascade cup in relation to the jet size for classic jet impingement activity to form. In fact, according to "classic" jet impingement theory, the block shouldn't perform as well as it does. I guess that's the difference between on-the-ground empericality, and theory. I don't pretend, on this one, to have enough of a clue to be able to derive theory for it. Am more interested in just making it work well through observation and experimenting.
[Edit: Said lower when I meant higher]