how would I stress test itYeah you'd want to see it tested, although when buying used you should pretty much always see it stress tested before buying it if you want to be safe.
Buying mining cards in general isn't a big issue in my opinion.
Any graphics stress test works really. Furmark, 3dMark, any of the Unigine tests. the goal is to run the card at full load and make sure that its stable and that it doesn't overheat.how would I stress test it