@FHuettig - thanks, we have no real disagreement at all.
The temps
ARE well within the 85 degree spec for the Zynq 7000 series, even with the 'stock' 'tin foil' attached heatsinks.
I suppose it's because I have a legacy mentality from being a computer hobbyist for decades. Heatsinks the size of grapefruits were once (are still?) the norm for an overclocked PC.
Still, something tells me that keeping a stable, low/lowish, temperature for any electronics system increases its life and uptime. Every little helps.
And it's a bit ironic that we're talking about a heat issue on an ARM-based chip, when the Parallella is a platform to demonstrate the low power/low heat Epiphany.
@optimaler - good stuff.
Card Stock sure beats 3D Printing when it comes to meeting deadlines!! Hope those are anti-static socks.
Larger standoffs will increase the overall height and you'll probably have to go back to stacked fans - or say, clusters of four per 'box' - or, say, different ducting between the boards. {....which can easilly get out of hand.}
... water cooling? Mmmmmm!
No surprise that properly applied Arctic silver is more efficient than the adhesive thermal tape, but thanks for the example and data. I'd planned on doing much the same.
The issue is how to safely and securely fix the heatsink when there are no holes/clips on the board. Card Stock won't help here, I'm afraid.
From the above, the thermal tape approach is deemed 'good enough' to stay within the spec for the Zynq - so I guess we're in the post sales, modding, hobbyist area as far as Adapteva is concerned.
I also wonder why there is variation between the boards which doesn't seem to tally with board position.
Is it because of differences in the 'tin foil' attachment (my guess), or because the Zynq's production output varies this much (I doubt/hope not)?
Note: My boards will be based on the smaller 7010 array, and I suspect they would have a marginally lower operating temp. Also, like here, I won't be using the HDMI circuitry which would have pushed the temps up higher still.
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