I put together VIM2, heatsink and Toneboard in DIY-case and run 2 hour FullHD movie on it using latest CoreELEC.
After 1 hours of playback CPU temp reached 75C (ambient temp was about 22C).
After 2 hours I stopped playback and let it cool down for 1 hour. Temp was 71C
As I understand - it is too hot. My minix u9h (same S912 as VIM2) maximum temp is 51C.
I tried to reapply thermal pad but without luck.
Is there any way to lower temperature without installing fan?
I am attempting to reproduce your result on our end. Do note that our ambient temperature is about 23 Degrees Celsius over here, as its winter time now.
I have also Toneboard installed on top of VIM2. All my videos are stored on NAS. CoreELEC is definitely able to play from usb, you just need to go to Videos and configure source. Later i will send some pictures, I’m not at home right now
73.8C is still within spec of the SoC, which puts max temperature at 105C.
Temperature increase is most likely caused by the disruption of convective airflow above the heatsink, as the Toneboard is mounted above the heatsink.
Solutions:
Most obvious would be to add forced-air-flow, rather than relying on passive convection, to carry heat away from the SoC.
Another solution would be to break-out the plastic plate on the bottom of your DIY Case, and install a thermal-pad to thermally-couple the SBC with the metal plate at the bottom of the case. Then the case itself should ideally be placed on a thermally conductive surface, or surface with sufficient mass to absorb the heat.