Placing the Parallella board on it's side/edge and cooling

[ArunD]

Hello.

Have a new Parallella and Porcupine boards that I purchased recently (May '15). At least for experimenting/prototyping I would like to place the boards once connected on their side/edge. The idea is that the Porcupine pins and connectors are easily accessible. The questions in the context are about keeping the board optimally cool:

- This article mentions that a fan is not required (or less important) if the board is placed on it's side. How do the comments apply to my setup where the heatsink that came with the board is glued to it?

- My imagination leads me to think that the board would be more effectively cooled when placed horizontally when the chips are facing upwards, with or without heatsink. When placed on edge the heat from lower half of the board would rise upwards and the upper half would tend to be warmer - so a fan would be more likely needed. This reasoning seems counter to article mentioned. Is it true, and why if not?

- Do I need to be concerned about ensuring air flow between the Parallella and the Porcupine boards?

- Does it matter which edge is preferrable if the board is placed on it's side?

- Any known failure and/or symptoms because of less than optimal cooling?

The comments in the forums lead me to believe that a fan is recommended even if a heatsink is glued. That the need may be more urgent depending on how the chips & setup are put to use. Also the understanding of the analysis of heating/cooling that Adapteva has done is not obvious to me at least to make any choices in this regards. Any edge condition issues, whether permanent or otherwise, that could occur because of insufficient/improper cooling may be hard to come to know. Prevention seems the best option by keeping a safe margin. Hence the context and questions.

[9600]

[tnt]

Note that the fan doesn't need to be big or fast.
The difference between no airflow and a very gently breeze is already a HUGE difference.