hpst What could RAM brand possibly have to do with any of this?
Hard to say, except both my 'good' Gigabyte G1 Gaming 970 cards are I believe Hynix RAM models. My 'bad' 970 (in a box) that is supposedly the same card with the same board revision, but different RAM and thus VBIOS, is Samsung memory, and that card does appear to have some subtle cooling differences, perhaps suggesting a variation in 1.0 version boards.
My reading about graphics chip models and especially the 970 suggested that Elpida RAM, as mentioned above with a 'good' card, was typically used on late model 970s. This is contrary to our theory that older 970s are the safe ones, and why I was interested in the make of card in question.