On Tue, Apr 3, 2018 at 5:01 PM, James Cameron <qu...@laptop.org> wrote:
> On Tue, Apr 03, 2018 at 10:33:12AM -0400, Adam Holt wrote: > > On Mon, Apr 2, 2018 at 12:36 PM, Adam Holt <[1]h...@laptop.org> wrote: > > > > On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt <[2]h...@laptop.org> > wrote: > > > > 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: > > > > vcgencmd measure_temp > > > > 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? > > ☆ With heatsink on CPU -- and without? > > ☆ With motherboard fully enclose by a case -- and without? > > > > My own results, with all 4 CPU's unloaded, in a chilly room: > > > > RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU > > 44-46C / 46-48C / 45-47C case's plastic top removed (w/o wind or active > > ventilation) > > 46-49C / 48-51C / 48-52C case's plastic top attached (contains 100+ > small holes > > on 1 end, allowing very little ventilation) > > > > After I ran "yes > /dev/null &" 4 times, to fully load all 4 cores > of the > > CPU: > > > > RPi 3 with-heatsink-on-CPU / RPi 3 B+ / RPi 3 B+ with-heatsink-on-CPU > > 80-82C / 70-71C / 71-72C case's plastic top removed (w/o wind or active > > ventilation) > > 82-84C / 75-78C / 79-82C case's plastic top attached (contains 100+ > small holes > > on 1 end, allowing very little ventilation) > > > > RESULT: attaching a heatsink to the RPi 3 B+ CPU does not help. It > might even > > make things a bit worse, hmm. > > Yes, your heatsink is no good. > > The B+ CPU has a heatsink or heat spreader already, that silver > coloured bevelled structure with the black dot and Broadcom logo. > > What is the shape, size, and attachment method for your added > heatsink? > It's the standard Canakit 7-fin aluminum heatsink shown here, attached to the CPU with its own basic 3M self-adhesive sticker: http://www.bestofjay.com/w/raspberry-pi-3-overclock-heat-test-flirc-case-vs-canakit-heatsink/ http://11986-presscdn-0-77.pagely.netdna-cdn.com/wp-content/uploads/2016/04/heat-sinks-installed.jpg 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 :) > 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!) > > > > > > 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. > > > > 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. > > > > 3) Prelim thermal analysis of RPi 3 B+: > > > > [3]https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODB > > MuHAw.png > > [4]https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi > > -3-b-plus-44122cf3d806 > > > > -- > > [5] > > [6]Unsung Heroes of OLPC, interviewed live @ [7] > http://unleashkids.org > > ! > > > > -- > > Unsung Heroes of OLPC, interviewed live @ [8] > http://unleashkids.org ! > > > > > > References: > > > > [1] mailto:h...@laptop.org > > [2] mailto:h...@laptop.org > > [3] https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI- > CODBMuHAw.png > > [4] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [5] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [6] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [7] http://unleashkids.org/ > > [8] http://unleashkids.org/ > > > _______________________________________________ > > Server-devel mailing list > > Server-devel@lists.laptop.org > > http://lists.laptop.org/listinfo/server-devel > > > -- > James Cameron > http://quozl.netrek.org/ > _______________________________________________ > Server-devel mailing list > Server-devel@lists.laptop.org > http://lists.laptop.org/listinfo/server-devel > -- Unsung Heroes of OLPC, interviewed live @ http://unleashkids.org !
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