There is an air-gap inside the chip packaging, so heatsinks on top will not provide any benefit, and according to Avalon will actually reduce the cooling performace. There is a thermal pad underneath the chip, which gets soldered to the PCB along with the contacts and then vias conduct the heat through the board to the heatsink on the opposite site. There's quite a reasonable discussion BkkCoin's Klondike thread about this.
We definitely plan on applying thermal paste correctly
We definitely plan on applying thermal paste correctly
Thanks. I read the thread and found what you mentioned. Seems a poor way to cool the chip but maybe they also didn't built the cooling into the PCB thing that well one could say, by looking at the temperatures posted by users.
Here is hoping you can come up with something better