better cooling on pinebook, the cheap way!

[schepers_cp]

first of all: i think there should be no throttling on any cpu under full load when testing it to the edge. (never had that my any laptop to be honest).
the pinebook is simply no exception in my opinion, but it throttles under certain loads due to heat.
hmm...
..
..how to tackle this?
EXTRA COOLING!

note: i won't say the pinebook is bad because of the throttling, i just want to mention this could be improved for a tiny bit of money (china is way cheaper than the eu anyway regarding hardware)

since i haven't received my pinebook yet.
but already know some details on how tight extra cooling can be to limit throttling, i thought of a bare bones cooling solution.

i looked at a small heatpipe, a small blower style fan, and copper film, all either too expensive or complicated for my use.
so i had to rethink my plan basically, and came across something very clever.

a material that is basically in almost every home, transfers heat as good as a heatsink (when applied correctly)
i'm talking about aluminum foil (tin foil called in america) which is practically a good heat spreader (because it's aluminum) and is thin, ideal for putting it between the case and the existing pinebook heatspreader

it won't be hard to make it work, just hard to apply (need to keep wrinkles down to a minimum on the SOC area)

a few layers over the soc extending over the battery area and towards the trackpad area should work nicely.
since most hardware is not within the area to cause damage, it should give almost zero risk of a short circuit (when applies correctly).

i'm planning to put in on the main board/keyboard/battery part of the laptop using some artic silver thermal paste i have, with a 1.6mm fully copper clad pcb i have laying around on top.
purely to let it fress nicely against the existing heatspreader when the bottom plate is screwed back on.
all will be secured with the existing case screws.

in total i plan on using 5 layers of aluminum foil of about 20cm x 10cm
costs: less than 2€ in the NL for a whole roll of aluminum (tin) foil of 3000cm x 30cm (30m x 0.3m), some thermal paste, plus a spare piece of (un)etched pcb, shim, spacer or similar (1.6mm x 30mm x 30mm).
imagine if this were done in china, it would cost around 1/5th of the €2 (0,40€), maybe even less

small lessons for this include: extra cooling isn't hard to accomplish, and is VERY cheap if you think clever.
this can be done in the factory as well (a bit more professional by sticking it all to the bottom plate), to prevent thermal throttling at those SOC intensive tasks and extend the lifespan of the device.
(we all know heat degrades devices over time)

i will let you guys know how it went (once i get my pinebook) and post the following thermals: SOC + PMIC.
all tested under these conditions while fully charged, at 50% backlight:
idle (cold start, booted into OS, idle for at least 5 minutes)
10min 4 thread stress test (same requirements as the idle test before this starts)
20min 4 thread stress test (same requirements as the idle test before this starts)
10 min watching youtube at 360p on firefox (same requirements as the idle test before this starts)

all under armbian 9 at room remp of 20 degrees C.

maybe in the future i will repeat the tests at 25 degrees C sometime, not sure

for now, anyone knows a good package for stressing the whole CPU? (where the slight throttling occurs at?)

(this post is merely a global info and placeholder for the final results till i've done this mod, which will described in this post)

[MarkHaysHarris777]

Throttling occurs at about 80℃.

As explained to you on irc more than once, throttling does not occur on the Pb under normal conditions and normal loads -- the current heat spreader does its job very well indeed.

I would not install aluminum foil in the case under any circumstances; that is asking for shorts. Obviously its your Pb (not until you get it of course) and you can do what you want with it;

Before you start modding the Pb, I would recommend that you wait until you actually have one and have tested it under load. I have been testing mine under load for some time and have found that there isn't a throttling issue under normal loads.

There are a number of ways to stress the cpu|gpu: I don't recommend any of them; most of them are not "normal" and do not represent normal loads nor normal use cases.

YMMV
( before you measure the gas mileage, get the car first and drive it around a bit )

[schepers_cp]

true that, i just want to make sure the temps get lower in general on the cheapest way possible.

and thanks for the warning about shorts, will be extra carefull when applying it. :O

i will apply the aluminum to measure the differences in temps for sure~

[schepers_cp]

just received my pinebook and am now going to swap the emmc to the 64gb variant, and add a copper sheet of 1.6mm thick using sticky thermal adhesive pads.
then load xenial mate onto it and test.