Concerning hardware there is nothing special about the built. Equipped with 4gb of DDR3 ram and a 28gb micro SD card connected via a sata adapter (later upgraded to 64gb SSD), the system can run a variety of OS. I decided to not build in a wifi card and stay "wired".

What bugged me where the two quite big aluminum passive cooling heat spreaders for the CPU and GPU. Each roughly 2cm tall. As I wanted a flat piece of PC I decided to custom build a passive cooling plate.

I decided to go with a 2mm thick massive copper plate on which I soldered some riser pads to exactly fit onto the CPU and GPU. I went with 2mm thickness for two reasons. First it doesn't bend and second my hope is that the amount of copper compensates for the reduced amount of surface area in comparison to the heat spreader.

Underside of SBC - riser copper plates.

Solder preparation - oak wooden veneer as separation layer between sbc and copper plate to avoid any short circuit.

First pad soldered

Both pads soldered and sanded - the colors are amazing - a piece of art.

Final assembly with ram, sd card, switches, led and battery

Top layer = oak veneer on 2mm wood fibre board,

bottom layer = pcb ontop of 2mm copper plate - inbetween wood veneer to avoid short-cuircuit.

Original aluminum heat spreaders. One for the CPU (Atom D2550) and one for the GPU (each 30mm by 30mm wide, 15mm tall)

temperature test on idel with the original heat spreaders (passive - no fan)

temperature test on idel with the copper heat spreader (passive - no fan)

final mini pc

oak veneer bottom

Conclusion:

the temperature tests showed clearly that the copper plate cooling solution has some design flaws. In the end I had to add a small fan to actively cool the CPU and GPU for acceptable temperatures. The copper plate has a surface area of 152,25 cm² whereas each aluminum heat spreader has a surface area of 111cm². Not only the total surface area is bigger but there are dedicated heat spreaders for each chip - so no heat transfer from one chip to the other occurs.

Was it a success ? Not really, a minimalistic passive cooling pc would have been nicer - but in the end my small form factor pc works well and is still quite silent with the active fan running.