by theover » Wed Apr 30, 2014 11:09 pm
The cooling is not needed to be better than inside the upper limit spec for most parts, but maybe these new chips have quamtum decay at some level, I don't know, that's rightly served by lower temperatures, an maybe the MOS chips are sensitive to moist still , and that that is less bad with lower temperatures. There are however parts that respond negative to higher temperatures: electrolytic capacitors, and I don't know if the number of decoupling capacitors probably on the various bif chips are free from this sensitivity. If there are relevant tantalum or elco parts (in SMD) on the little board, it could better stay in 50 degrees Celcius range if it's on often, to keep the lifetime of those parts good.
It makes the same sense in computer pcbs in general, keep them cool, and they last long, if not, they may well break, I know from practice. SO to keep a cluster working 24/7 for long, it might be advantageous to keep full power available for top speed on all parts while keeping the temp low, mainly this is easy by using a well-conducting bigger heatsink, that's probably easiest and most effective. I might even want to cool passive by simpling connecting a large enough heatsink.
Of course there's special thermal paste, which i've used to conduct a hundred or 250W away from I7s in optomal sense, but the size of and the airflow over a heatsink is more important, and 10 Watts or so per board isn't extreme, a decent moderate sized heatsink, one size class bigger than the super-tiny provided one should be ok. Howto put that on a cluster is another matter, maybe a big thick piece of aluminum per board connecting to a side-coolfin.
T.