Well, what does the bluescreen actually say about which module caused the crash? It's possible that this is graphics card related, but just blindly blaming the card or driver doesn't make it so...
Good question. Are you refering to what is printed on the bluescreen? I don't always look! When I have looked, it has identified various apps that were running at the time. However, I don't think that is accurate for identifying the source of the problem, because this occurs even when no other apps are running. Because of the way it progressively slows down, it seems to me that there is a memory issue somewhere in the pipeline. I can imagine that 16bpc color increases the memory requirement signficantly, that's why I'm suspicious of an older video card (even though its high end).
I'm considering converting all my 3D sequences using a 16bpc project, then doing importing them into an 8bpc project to add effects... does that seem worthwhile?
You keep mentioning video cards. They have NOTHING to do with rendering in AE. Thus, if you're trying to use Open GL to accelerate your renders, turn it off and leave it off. Open GL rarely helps and all too often hurts.