<div dir="ltr">On Tue, Apr 3, 2018 at 5:01 PM, James Cameron <span dir="ltr"><<a href="mailto:quozl@laptop.org" target="_blank">quozl@laptop.org</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Tue, Apr 03, 2018 at 10:33:12AM -0400, Adam Holt wrote:<br>
> On Mon, Apr 2, 2018 at 12:36 PM, Adam Holt <[1]<a href="mailto:holt@laptop.org">holt@laptop.org</a>> wrote:<br>
<div><div class="gmail-h5">><br>
> On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt <[2]<a href="mailto:holt@laptop.org">holt@laptop.org</a>> wrote:<br>
><br>
> 1) Recap from 2016: heatsinks on the original RPi3 CPU are not a<br>
> cure-all when the RPi 3 is enclosed in a case that lacks ventilation on<br>
> a hot day. But CPU heatsinks Do Work when taking the plastic top off<br>
> the of the original RPi 3. The CPU throttling problem "immediately"<br>
> goes away on such hot days...bringing the temperature back down below<br>
> 80C...as measured by the command:<br>
><br>
> vcgencmd measure_temp<br>
><br>
> 2) It's snowing today right outside my window, so I can't easily<br>
> simulate a hot summer's day -- but can others who live in hot<br>
> environments report back their readings above, when running the new<br>
> RPi3 B+ in various conditions?<br>
> ☆ With heatsink on CPU -- and without?<br>
> ☆ With motherboard fully enclose by a case -- and without?<br>
><br>
> My own results, with all 4 CPU's unloaded, in a chilly room:<br>
><br>
> RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU<br>
> 44-46C / 46-48C / 45-47C case's plastic top removed (w/o wind or active<br>
> ventilation)<br>
> 46-49C / 48-51C / 48-52C case's plastic top attached (contains 100+ small holes<br>
> on 1 end, allowing very little ventilation)<br>
><br>
> After I ran "yes > /dev/null &" 4 times, to fully load all 4 cores of the<br>
> CPU:<br>
><br>
> RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU<br>
> 80-82C / 70-71C / 71-72C case's plastic top removed (w/o wind or active<br>
> ventilation)<br>
> 82-84C / 75-78C / 79-82C case's plastic top attached (contains 100+ small holes<br>
> on 1 end, allowing very little ventilation)<br>
><br>
> RESULT: attaching a heatsink to the RPi 3 B+ CPU does not help. It might even<br>
> make things a bit worse, hmm.<br>
<br>
</div></div>Yes, your heatsink is no good.<br>
<br>
The B+ CPU has a heatsink or heat spreader already, that silver<br>
coloured bevelled structure with the black dot and Broadcom logo.<br>
<br>
What is the shape, size, and attachment method for your added<br>
heatsink?<br></blockquote><div><br></div><div>It's the standard Canakit 7-fin aluminum heatsink shown here, attached to the CPU with its own basic 3M self-adhesive sticker:<br><br><a href="http://www.bestofjay.com/w/raspberry-pi-3-overclock-heat-test-flirc-case-vs-canakit-heatsink/">http://www.bestofjay.com/w/raspberry-pi-3-overclock-heat-test-flirc-case-vs-canakit-heatsink/</a><br><a href="http://11986-presscdn-0-77.pagely.netdna-cdn.com/wp-content/uploads/2016/04/heat-sinks-installed.jpg">http://11986-presscdn-0-77.pagely.netdna-cdn.com/wp-content/uploads/2016/04/heat-sinks-installed.jpg</a><br><br></div><div>FWIW these same heatsinks do lower the temperature of the original RPi 3 by many degrees IF the CPU 's under medium load AND the top of the plastic case is removed :)<br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<span class="gmail-">> In any case: this result is completely different the original RPi 3 (where past<br>
> experiments have shown that a heatsink-on-CPU greatly lowers its temperature,<br>
> When The Case Is Open!)<br>
> <br>
><br>
> CONCLUSION: the RPi 3 B+ appears to be a real winner in CPU-intensive<br>
> conditions, even in a "wintry" conditions (room is about 15C, and it<br>
> continues to snow right outside the window). The RPi 3 CPU is supposed to<br>
> self-throttle at 80C, until it just about turns itself off at 85C. I'd<br>
> assume the RPi 3 B+ CPU does the same? But do not know for sure. Thanks<br>
> to all who can add any similar data points, in warmer climate/conditions.<br>
><br>
> CLARIFS: Both RPi's were running a near-final prerelease of<br>
> Internet-in-a-Box 6.5 on Raspbian Lite to explore real-world conditions. <br>
> I waited 10+ min in all above 8 experiments before taking "steady state"<br>
> temp readings. Still, fluctuations in CPU activity (and temperature)<br>
> arise, even long after I ran "killall yes" to end the most intensive CPU<br>
> activity.<br>
><br>
> 3) Prelim thermal analysis of RPi 3 B+:<br>
><br>
</span>> [3]<a href="https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODB" rel="noreferrer" target="_blank">https://cdn-images-1.<wbr>medium.com/max/1600/1*0jU89Yu_<wbr>6miI-CODB</a><br>
> MuHAw.png<br>
> [4]<a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi" rel="noreferrer" target="_blank">https://medium.com/@<wbr>ghalfacree/benchmarking-the-<wbr>raspberry-pi</a><br>
> -3-b-plus-44122cf3d806<br>
><br>
> --<br>
> [5]<br>
> [6]Unsung Heroes of OLPC, interviewed live @ [7]<a href="http://unleashkids.org" rel="noreferrer" target="_blank">http://unleashkids.org</a><br>
> !<br>
><br>
> --<br>
> Unsung Heroes of OLPC, interviewed live @ [8]<a href="http://unleashkids.org" rel="noreferrer" target="_blank">http://unleashkids.org</a> !<br>
><br>
><br>
> References:<br>
><br>
> [1] mailto:<a href="mailto:holt@laptop.org">holt@laptop.org</a><br>
> [2] mailto:<a href="mailto:holt@laptop.org">holt@laptop.org</a><br>
> [3] <a href="https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODBMuHAw.png" rel="noreferrer" target="_blank">https://cdn-images-1.medium.<wbr>com/max/1600/1*0jU89Yu_6miI-<wbr>CODBMuHAw.png</a><br>
> [4] <a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" rel="noreferrer" target="_blank">https://medium.com/@<wbr>ghalfacree/benchmarking-the-<wbr>raspberry-pi-3-b-plus-<wbr>44122cf3d806</a><br>
> [5] <a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" rel="noreferrer" target="_blank">https://medium.com/@<wbr>ghalfacree/benchmarking-the-<wbr>raspberry-pi-3-b-plus-<wbr>44122cf3d806</a><br>
> [6] <a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" rel="noreferrer" target="_blank">https://medium.com/@<wbr>ghalfacree/benchmarking-the-<wbr>raspberry-pi-3-b-plus-<wbr>44122cf3d806</a><br>
> [7] <a href="http://unleashkids.org/" rel="noreferrer" target="_blank">http://unleashkids.org/</a><br>
> [8] <a href="http://unleashkids.org/" rel="noreferrer" target="_blank">http://unleashkids.org/</a><br>
<div class="gmail-HOEnZb"><div class="gmail-h5"><br>
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<br>
<br>
--<br>
James Cameron<br>
<a href="http://quozl.netrek.org/" rel="noreferrer" target="_blank">http://quozl.netrek.org/</a><br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature"><div dir="ltr">Unsung Heroes of OLPC, interviewed live @ <a href="http://unleashkids.org" target="_blank">http://unleashkids.org</a> !</div></div>
</div></div>