On Tue, Apr 3, 2018 at 8:17 PM, James Cameron <qu...@laptop.org> wrote:
> On Tue, Apr 03, 2018 at 05:28:31PM -0400, Adam Holt wrote: > > On Tue, Apr 3, 2018 at 5:01 PM, James Cameron <[1]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][2]h...@laptop.org> > wrote: > > > > > > On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt <[2][3] > 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: > > > > [4]http://www.bestofjay.com/w/ > > raspberry-pi-3-overclock-heat-test-flirc-case-vs-canakit-heatsink/ > > [5]http://11986-presscdn-0-77.pagely.netdna-cdn.com/wp- > content/uploads/2016/04/ > > heat-sinks-installed.jpg > > Given your results, probably wrong heatsink for the job. No, I don't > know of a better one. > Indeed. It'd be really great if the Raspberry Pi Foundation would publish basic recommendations here, even if just community/testing suggestions. Theory; the adhesive won't make good contact with outer bevel, and > passive airflow above that outer bevel will be reduced. > > Theory; bubble in adhesive if the heatsink was not angled slightly as > you pushed it down. > > Theory; the thermal control system is very different to the previous > version, and this invalidates your test method. The system uses > thermal mass and core frequency scaling, and you've changed the > thermal mass. It's non-linear. > > Report your kernel version; the corresponding Raspbian release has > changes for the B+. > Kernel is 4.14.30-v7+ after 2018-03-28's Raspbian update ("apt update; apt dist-upgrade; reboot"). See > https://www.raspberrypi.org/blog/raspberry-pi-3-model-bplus-sale-now-35/ > for more technical detail on the thermals; note how the core frequency > varies and the thermal mass is a resource. > > Suggest you use sysbench for at least 15 minutes before reading the > temperature. The "yes" test is very weak. > Thanks. Any recommended parameters for sysbench to battle-test all RPi 3 B+ subsystems simultaneously? > 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 :) > > But irrelevant, as the CPU is a different model, has a flat surface, > and does not have a thermal control system that uses thermal mass. > > Please remember; things change, and this breaks your knowledge. You > must learn again. > > > > > > 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][6]https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_ > > 6miI-CODB > > > MuHAw.png > > > [4][7]https://medium.com/@ghalfacree/benchmarking-the- > > raspberry-pi > > > -3-b-plus-44122cf3d806 > > > > > > -- > > > [5] > > > [6]Unsung Heroes of OLPC, interviewed live @ [7][8]http:// > > unleashkids.org > > > ! > > > > > > -- > > > Unsung Heroes of OLPC, interviewed live @ [8][9]http:// > > unleashkids.org ! > > > > > > > > > References: > > > > > > [1] mailto:[10]h...@laptop.org > > > [2] mailto:[11]h...@laptop.org > > > [3] [12]https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI- > > CODBMuHAw.png > > > [4] [13]https://medium.com/@ghalfacree/benchmarking-the- > > raspberry-pi-3-b-plus-44122cf3d806 > > > [5] [14]https://medium.com/@ghalfacree/benchmarking-the- > > raspberry-pi-3-b-plus-44122cf3d806 > > > [6] [15]https://medium.com/@ghalfacree/benchmarking-the- > > raspberry-pi-3-b-plus-44122cf3d806 > > > [7] [16]http://unleashkids.org/ > > > [8] [17]http://unleashkids.org/ > > > > > _______________________________________________ > > > Server-devel mailing list > > > [18]Server-devel@lists.laptop.org > > > [19]http://lists.laptop.org/listinfo/server-devel > > > > -- > > James Cameron > > [20]http://quozl.netrek.org/ > > _______________________________________________ > > Server-devel mailing list > > [21]Server-devel@lists.laptop.org > > [22]http://lists.laptop.org/listinfo/server-devel > > > > -- > > Unsung Heroes of OLPC, interviewed live @ [23]http://unleashkids.org ! > > > > References: > > > > [1] mailto:qu...@laptop.org > > [2] mailto:h...@laptop.org > > [3] mailto:h...@laptop.org > > [4] http://www.bestofjay.com/w/raspberry-pi-3-overclock-heat- > test-flirc-case-vs-canakit-heatsink/ > > [5] http://11986-presscdn-0-77.pagely.netdna-cdn.com/wp- > content/uploads/2016/04/heat-sinks-installed.jpg > > [6] https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODB > > [7] https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi > > [8] http://unleashkids.org/ > > [9] http://unleashkids.org/ > > [10] mailto:h...@laptop.org > > [11] mailto:h...@laptop.org > > [12] https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI- > CODBMuHAw.png > > [13] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [14] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [15] https://medium.com/@ghalfacree/benchmarking-the- > raspberry-pi-3-b-plus-44122cf3d806 > > [16] http://unleashkids.org/ > > [17] http://unleashkids.org/ > > [18] mailto:Server-devel@lists.laptop.org > > [19] http://lists.laptop.org/listinfo/server-devel > > [20] http://quozl.netrek.org/ > > [21] mailto:Server-devel@lists.laptop.org > > [22] http://lists.laptop.org/listinfo/server-devel > > [23] 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 > > -- > <http://lists.laptop.org/listinfo/server-devel> > <http://lists.laptop.org/listinfo/server-devel> > Unsung Heroes of OLPC, interviewed live @ > <http://lists.laptop.org/listinfo/server-devel>http://unleashkids.org ! >
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