The DC/DC chip on ethernet controller handles inputs from 5 to 12V. We tested cases of 5V and 12V and both work.
We also tested the temperature using thermal pads and not using. There are only negligible differences. This is why we marked them as optional. On the other hand, the current thermal pad solution may introduce bubbles which worsens the temperature in some local area. So we do no install them by default, but still ship them along in case there is any rare situation when the back of PCB is damaged and becomes conductive.
Thanks for the info, so if you don't use the thermal pads or any paste it won't void the boards warranty?
I did notice today when I pulled a bad board to send back to Canary the pad had developed 2 large bubbles in it and I had it good and flat when I installed it. Would you recommend not using it?
I installed my boards the same way you would install a cylinder head on an engine, center to end alternating sides. I figure this will minimize
bubbles.