Heatsink modding

[scropion86]

Blow "fresh/cool" air to/at/over/through the heatsink...
The best way would be to find a way to transport this warmed up air directly (as possible) out of the device...

i tried that with laptop blower fan to blow the air out of the box
and after testing with and without the fan , i can only say it's useless idea as i got only 2-5 C down.

i taken out the PCB out and using it like that after i places 2 heatsinks on the alu plate on the CPU
and this keeps my core temp average on 65-70 C for now it's acceptable .

my new plan to get 35MM X 65MM X 17MM copper block and to connect between the CPU plate and the Pipo body.

but that require changing the stand-off that holds the PCB and the other one that lock the device
i found the way on that post http://www.freaktab.com/showthread.p...-PCB-stand-off
but i am still searching for the stand-off to start

[no_spam_for_me]

Yes, but I don't talk about "blow the air out of the box"... I talk about blowing the air over a heatsink, and at best case to find a way to transport this air (after it passes the heatsink) out of the box...

[geppetto61]

Yes, but I don't talk about "blow the air out of the box"... I talk about blowing the air over a heatsink, and at best case to find a way to transport this air (after it passes the heatsink) out of the box...

Hi and thanks a lot. The concept is much clearer now to me.
The "fresh" air must be pushed against the device to be cooled down.
Blown towards it like when we want to cool something with the mouth

I guess that the top side of the PCB is the hotter compared to the bottom side.
Maybe even just a series some small holes in the upper case could improve ventilation inside the case ... the holes will let the hot air above the pcb out of the case naturally.
I think that the passive cooling should be kept ... it is a very nice thing when it works.
Thanks again

[scropion86]

maybe your way to blow the air into the heatsink will drop the Temp more than my case , but
with my fan i cant fix it to blow the air into the heatsink as no room for that because of the stand-off
that holds the PCB.

but in theory hot air that blown out will be replaced by a cold fresh air from the out side
as the box has ventilations from both sides and also under the PCB if you didn’t close it with thermal pads
I also tried to make the box stand vertically to get the chimney effect and that makes also a small difference.

I suggest to make the box stand and the fan to blow out the air toward the heatsink and that will get the hot air faster out of the box

[geppetto61]

Hi i think that adding a fan can be very tempting but also challenging.
I would try to stay passive after all ... it is a big plus for a unit being stable with just passive cooling even when the HW is pushed to its limits.
Maybe some holes drilled in strategic points can help as well.
Thanks a lot for the valuable advice

[virusX]

Maybe some holes drilled in strategic points can help as well.

I turned my X7 upside down... Free holes !

[scropion86]

I turned my X7 upside down... Free holes !

but please note that most of the hot air coming from the top side of CPU which became under the PCB after you flipped the BOX upside down , so most of the hot air will be trapped under the PCB and that's maybe lead to increase the Core temp after all.

you should do a short stress test for both options and let the Device to cool down totally in between
after that compare the results and of course share it Here

[virusX]

Perhaps the PCB will be heating a bit but not trapped, the hot air will flow outside the box as it got some other holes on the side but I don't think I got temperature problem at first place.
I did it without thinking much and left it like that.
I'll monitor that to see what's going on temperature wise.
PS: your avatar is my desktop wallpaper at work

[geppetto61]

Perhaps the PCB will be heating a bit but not trapped, the hot air will flow outside the box as it got some other holes on the side but I don't think I got temperature problem at first place.
I did it without thinking much and left it like that.
I'll monitor that to see what's going on temperature wise.
PS: your avatar is my desktop wallpaper at work

Hi and thanks this will be very interesting and telling i think.
But i also guess that the cpu is indeed the hottest part (a thermal picture would be nice )and if the holes are drilled carefully they should not ruin the look of the unit at all and they should improve the air flow inside the unit.
Actually i am wondering if the bottom plate is really needed ... the pcb looks attached to the upper frame/chassis like suspended ?
so why not a bottomless case left completely open on the bottom ?
Thanks a lot for the very interesting thread.

[loko]

Thanks for the tip. I will file that away for future use. Your advice and support is invaluable. Thanks again,
Kevin

You are welcome.

so why not a bottomless case left completely open on the bottom ?

If the case is completely open, you could short the mainboard easier and fry the device. If you do not plan to move your device at all, I guess it could be fine. Try to operate the device without the bottom cover for a while and see if the risk can be justified.

[vertical]

It will definitely be worse. You want to extract heat from the processor as quick as possible.

Copper has a 400 W/mK thermal conductivity, Aluminium has 200 W/mK thermal conductivity, Thermal Pastes have a 5-10 W/mK thermal conductivity, Thermal Pads have a 1-5 W/mK thermal conductivity, while Thermal Adhesive Tapes have a 1 W/mK thermal conductivity.

If you put extra thermal pads between the processor and the actual heat sink, you will increase the total thermal resistance, thus you will decrease the total thermal conductance.

So, my second alternative is to put the heatsinks directly on the metallic plate covering the CPU. I have two options:

a) Use this akasa adhesive tape to keep the heatsinks in place. Although in the link it says not for CPUs because it is not designed for quick removal.
b) Use arctic silver 5. I am not sure though if the heatsinks can stay in place just with the AS5 and not slip away. I have been using AS5 for years but usually on heatsinks/coolers that can clip on the motherboards.

[virusX]

but please note that most of the hot air coming from the top side of CPU which became under the PCB after you flipped the BOX upside down , so most of the hot air will be trapped under the PCB and that's maybe lead to increase the Core temp after all.

you should do a short stress test for both options and let the Device to cool down totally in between
after that compare the results and of course share it Here

I've done some stress test yesterday and this morning on my unmodified Pipo X7.
The results shows that it's a bad idea to turn the device upside down scropion86

Room temp ~22°C - Aida64 trial
The temps are CORE temps from Aida64.

Upside down: 70°C (1h idle) -> 10mn stress ~80°C
Normal position: ~42°C (just booted) -> 20mn stress 78°C max/~72°C average
No throttling. It goes back to ~62°C after 3 minutes.

Is 78°C really bad ? I ask because I don't get any reboot or issue at those temps playing 720p videos and emulated games.
From the z36xx/z37xx datasheets:
SDP is set to 90°C, the throttling is triggered at 100°C and got a max temp at 105°C.
But I couldn't find a reference for working temp of the Z3736F

[loko]

Although in the link it says not for CPUs because it is not designed for quick removal.

Not recommended for CPU or GPU usage means that you should not stick it directly to the chip. Sticking it on a removable metal plate is a totally different case. You can even use permanent thermal adhesive paste to achieve better thermal results.

But I couldn't find a reference for working temp of the Z3736F

There are Tjmax 90ºC and 105ºC packages. Z3736F goes up to 90ºC, then it gets probably fried.

1.3 SKU Information
Table 1. SoC SKU List

http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z36xxx-z37xxx-datasheet-vol-1.pdf

[trebor]

Save a bit of reading

[kgian76]

My 5mm thermal pad from Germany just arrived. I am going to try it today and report my findings. It better be good as it was expensive!