My memory says it was already discussed, but the posts must have been deleted:
Heatsinks are never made of "stainless". It conducts heat extremely poorly. What is really at play is chrome-plated aluminum, which has a mirror-like finish.
Well, that's why the word is in "quotes", isn't it? It's only to differentiate it from the thick-finned aluminum one.
So, performance wise by the numbers, the copper heat sink still takes it home, the metal heat sink comes in second and the aluminum heat sink comes in last. Common knowledge is that the metal heat sink sucks, is useless, should be avoided etc. but these temperature readings show otherwise. What does make the metal heat sink a poor choice is the system instability it somehow causes. - House of Moth
It's been said before, but stuff gets lost or just unseen in a gazillion posts, so I'll repeat:The copper sink with the heat pipes, although it's the most efficient of the three with original Apple 7450s,
cannot, repeat cannot be used with the Sonnet MDX card!The 7447's are NOT located in exactly the same place and only one of them will cool properly. The other one
will overheat and die.
I too, tried all of the sinks and settled on the "stainless" for that reason. It was disappointing for sure, as I had previously had a 2x1.42 Xserve CPU card in there with the copper sink and it was clearly the coolest one…
It's a trap waiting to spring since you can't actually
see they don't align properly when installing the sink. You can only tell if you pull it up again and notice the compound is partly undisturbed over one CPU.
As for the Moth saying the stainless causes some kind of mystery "instability", that is not my experience at all. I haven't had a crash or the smallest hiccup even once. I suspect that a
lot of people with little or no knowledge of thermodynamics are also doing amateur fan changes and mods at the same time. The MDD was called the "wind tunnel" because that was how it was designed. It needed to move a LOT of air through a cluttered, tight space with the main fan and it ended up generating probably a LOT more noise than they would have liked but they were married to the case design and it was the last G4 built, using Xserve stuff, to fill the gap behind the G5 that was taking forever to finish… so long that they soon even had to add another stopgap model for LESS money, the FW800. It's never a good thing when you have to offer an entire new PSU and fan to your customers
FOR FREE because you've sold them the noisiest home computer ever made.
What's equally as remarkable is that you would think after all that, the G5 would have been whisper-quiet. Oops…