Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[James Cameron]

On Tue, Apr 03, 2018 at 08:35:54PM -0400, Adam Holt wrote:
> On Tue, Apr 3, 2018 at 8:17 PM, James Cameron <[1]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][2]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][3]
> h...@laptop.org> wrote:
> >     >
> >     >     On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt <[2][3][4]
> 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][5]http://www.bestofjay.com/w/
> > raspberry-pi-3-overclock-heat-test-flirc-case-vs-canakit-heatsink/
> > 
> [5][6]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.

Best tell them.

> 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
> 
> [7]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
>

Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[Adam Holt]

On Tue, Apr 3, 2018 at 8:17 PM, James Cameron  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.
>

Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[James Cameron]

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.

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+.

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.

> 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?  

Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[Adam Holt]

On Tue, Apr 3, 2018 at 5:01 PM, James Cameron  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/
>
> > 

Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[James Cameron]

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?

> 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/

> ___
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> http://lists.laptop.org/listinfo/server-devel


-- 
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http://quozl.netrek.org/
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Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[James Cameron]

On Tue, Apr 03, 2018 at 09:07:22AM -0400, Adam Holt wrote:
> On Tue, Apr 3, 2018 at 1:53 AM, James Cameron <[1]qu...@laptop.org> wrote:
> 
> Temperature readings are not comparable between RPi 3 and RPi 3 B+
> because of throttling differences, and the metal heat spreader.
> 
> Ambient temperature is critical for the separate chip used for
> Ethernet and USB; it has a lower maximum operating temperature than
> the CPU.
> 
>  
> Do you happen to know this chip's max operating temperature spec?

Only 70 degrees C.

http://www.microchip.com/wwwproducts/ProductCompare/LAN7515/LAN9514

This looks like a binning threshold.

Let me spin a story.  The manufacturer of the chip tests the operating
temperature range using some method, and separates the results into
four bins;

- operates above 86, into the bin labelled "excellent",

- operates above 70 and below 86, into the bin labelled "industrial",

- operates above 60 and below 71, into the bin labelled "commercial",

- doesn't operate above 70, into the bin labelled "throw away".

Then what happens next is often surprising;

1.  if a customer orders the industrial version, it will be filled
from the "industrial" and then the "excellent" bin,

2.  if a customer orders the commercial version, it will be filled
from the "commercial", "industrial" and then the "excellent" bins.

The chips can be encapsulated and labelled at any time, before or
after this binning.

So you as customer of customer only knows it will operate to 70, and
it might operate to 85.

The chip heats from being powered, and from Ethernet and USB activity.

The heat from the CPU will bleed across to the chip.  In a normal
enclosure, this isn't a problem.  In a sealed enclosure with no air
flow, and high CPU, Ethernet and USB activity, it could be more
interesting.

It would be reasonably easy to test for; if the CPU temperature does
not fall rapidly when activity slows, it is because the board and
air nearby has reached equilibrium with the CPU.

> Your best comparison will be between timings of equal workloads with
> equal cooling in identical environment.
> 
> You can't do this honestly with temperature alone.
>
> --
> James Cameron
> [2]http://quozl.netrek.org/
> ___
> Server-devel mailing list
> [3]Server-devel@lists.laptop.org
> [4]http://lists.laptop.org/listinfo/server-devel
> 
> --
> [5]
> [6]Unsung Heroes of OLPC, interviewed live @ [7]http://unleashkids.org !
> 
> References:
> 
> [1] mailto:qu...@laptop.org
> [2] http://quozl.netrek.org/
> [3] mailto:Server-devel@lists.laptop.org
> [4] http://lists.laptop.org/listinfo/server-devel
> [5] http://lists.laptop.org/listinfo/server-devel
> [6] http://lists.laptop.org/listinfo/server-devel
> [7] http://unleashkids.org/

> ___
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> http://lists.laptop.org/listinfo/server-devel


-- 
James Cameron
http://quozl.netrek.org/
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Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[Adam Holt]

On Mon, Apr 2, 2018 at 12:36 PM, Adam Holt  wrote:

> On Mon, Apr 2, 2018 at 10:44 AM, Adam Holt  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.*
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+:
>>
>> https://cdn-images-1.medium.com/max/1600/1*0jU89Yu_6miI-CODBMuHAw.png
>> https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi
>> -3-b-plus-44122cf3d806
>>
>> --
>>
>> 
>>
>> 
>> Unsung Heroes of OLPC, interviewed live @
>> 
>> http://unleashkids.org !
>>
>> --
>> Unsung Heroes of OLPC, interviewed live @ http://unleashkids.org !
>>
>
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Re: [Server-devel] do RPi 3 B+ still need heat sinks?

[Adam Holt]

On Tue, Apr 3, 2018 at 1:53 AM, James Cameron  wrote:

> Temperature readings are not comparable between RPi 3 and RPi 3 B+
> because of throttling differences, and the metal heat spreader.
>
> Ambient temperature is critical for the separate chip used for
> Ethernet and USB; it has a lower maximum operating temperature than
> the CPU.
>

Do you happen to know this chip's max operating temperature spec?

Your best comparison will be between timings of equal workloads with
> equal cooling in identical environment.
>
> You can't do this honestly with temperature alone.
>
> --
> 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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