I've been wondering about this for a while and my usual resources don't seem to really know.
The base question is; which 3D card performs the best on Linux (any distro)?
But of course, the question is really two-fold;
1) What's the best bet, performance-wise, if I insist on using strictly open-source drivers with no closed firmware or anything of the sort?
2) If the best performance can only be acquired with closed-source drivers or/or closed firmware, what's the best bet?
I am flabbergasted by how difficult it is to get people to even tell me anything at all about this. I don't know how to ask this in a better way so I'm leaving it closed.