<div dir="ltr">On Mon, Apr 2, 2018 at 12:36 PM, Adam Holt <span dir="ltr"><<a href="mailto:holt@laptop.org" target="_blank">holt@laptop.org</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><span>On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt <span dir="ltr"><<a href="mailto:holt@laptop.org" target="_blank">holt@laptop.org</a>></span> wrote:<br></span><div class="gmail_extra"><div class="gmail_quote"><span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>1) Recap from 2016: heatsinks on the original RPi3 CPU are not a cure-all when the RPi 3 is enclosed in a case that lacks ventilation on a hot day. But CPU heatsinks Do Work when taking the plastic top off the of the original RPi 3.
The CPU throttling problem "immediately" goes away on such hot days...bringing the temperature back down below 80C...as measured by
the command:<br><div><br> <b><span class="m_-3346273889403328340m_4879647057915600924m_-3366861160933038683gmail-m_-3334770784490450069gmail-st">vcgencmd measure_temp</span></b>
<br></div><div><br></div>2)
It's snowing today right outside my window, so I can't easily simulate a hot summer's day --
but can others who live in hot environments report back their readings above, when running the new RPi3 B+ in various conditions?<b><br></b><ul><li><b>With heatsink on CPU -- and without?</b></li><li><b>With motherboard fully enclose by a case -- and without?</b></li></ul></div><div></div></div></blockquote><div><br></div></span><div>My own results, with all 4 CPU's unloaded, in a chilly room:<br></div></div></div></div></blockquote><div><br> RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU<span style="background-color:rgb(0,255,0)"><br>44-46C</span> / <span style="background-color:rgb(106,168,79)">46-48C</span> / <span style="background-color:rgb(106,168,79)">45-47C</span> case's plastic top removed (w/o wind or active ventilation)<span style="background-color:rgb(106,168,79)"><br>46-49C</span> / <span style="background-color:rgb(56,118,29)">48-51C</span> / <span style="background-color:rgb(56,118,29)">48-52C</span> case's plastic top attached (contains 100+ small holes on 1 end, allowing very little ventilation)<br><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>After I ran "<b>yes > /dev/null &</b>" 4 times, to fully load all 4 cores of the CPU:<br></div></div></div></div></blockquote><div><br>
RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU<span style="background-color:rgb(0,255,0)"></span><span style="background-color:rgb(224,102,102)"><br>80-82C</span> / <span style="background-color:rgb(255,255,0)">70-71C</span> / <span style="background-color:rgb(255,255,0)">71-72C</span> case's plastic top removed
(w/o wind or active ventilation)
<span style="background-color:rgb(255,0,0)"><br>82-84C</span> / <span style="background-color:rgb(255,153,0)">75-78C</span> / <span style="background-color:rgb(224,102,102)">79-82C</span> case's plastic top attached
(contains 100+ small holes on 1 end, allowing very little ventilation)<br><br></div><div><i>RESULT: attaching a heatsink to the RPi 3 B+ CPU does not help. It might even make things a bit worse, hmm.<br></i><br>In any case: this result is completely different the original RPi 3 (where past experiments have shown that a heatsink-on-CPU greatly lowers its temperature, When The Case Is Open!)<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>CONCLUSION: the RPi 3 B+ appears to be a real winner in CPU-intensive conditions, even in a "wintry" conditions (room is about 15C, and it continues to snow right outside the window). The RPi 3 CPU is supposed to self-throttle at 80C, until it just about turns itself off at 85C. I'd assume the RPi 3 B+ CPU does the same? But do not know for sure. Thanks to all who can add any similar data points, in warmer climate/conditions.<br><br><br>CLARIFS:
Both RPi's were running a near-final prerelease of Internet-in-a-Box 6.5 on Raspbian Lite to explore real-world conditions.
I waited 10+
min in all above 8 experiments before taking "steady state" temp readings. Still, fluctuations in CPU activity (and temperature) arise, even long after I ran "killall yes" to end the most intensive CPU activity.<br><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"><div dir="ltr"><div><span>3) Prelim thermal analysis of RPi 3 B+:<br><br><a href="https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODBMuHAw.png" target="_blank">https://cdn-images-1.medium.co<wbr>m/max/1600/1*0jU89Yu_6miI-CODB<wbr>MuHAw.png</a><b><br></b></span><a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" target="_blank">https://medium.com/@ghalfacree<wbr>/benchmarking-the-raspberry-pi<wbr>-3-b-plus-44122cf3d806<span class="m_-3346273889403328340HOEnZb"><font color="#888888"><br clear="all"><br>-- <br></font></span></a><span class="m_-3346273889403328340HOEnZb"><font color="#888888"><div class="m_-3346273889403328340m_4879647057915600924m_-3366861160933038683gmail_signature"><a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" target="_blank"></a><div dir="ltr"><a href="https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-3-b-plus-44122cf3d806" target="_blank">Unsung Heroes of OLPC, interviewed live @ </a><a href="http://unleashkids.org" target="_blank">http://unleashkids.org</a> !<br clear="all"><br>-- <br><div class="m_-3346273889403328340gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Unsung Heroes of OLPC, interviewed live @ <a href="http://unleashkids.org" target="_blank">http://unleashkids.org</a> !</div></div>
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