Reply 20 of 25, by frudi
I understand what the problem with the underfill was and why it lead to bumps failing. My objection wasn't that this isn't happening, merely to the idea that the problem would be exacerbated with passively cooled cards.
My experience with passive cards has been that while they run hotter under load, they also run a lot hotter while idle, meaning they effectively experience lesser temperature variations between load and idle temperatures than actively cooled cards. And while they heat up faster, they cool off a lot slower, which would again reduce thermal stresses.
At least, that was my reasoning. Though now, based on what you say, I'm thinking because bumps are so small, so close to the heat source (while also producing heat themselves) and opposite side of the cooling surface, that active versus passive cooling likely doesn't have much influence on thermal conditions in the bumps and underfill anyway. So there wouldn't be much if any difference in how passive and active cards are affected by this defect. Or am I understanding something wrong?
