After the another-stupid-cryptocurrency fad making AMD Polaris cards rare has ended, "miners" are apparently dumping their hardware.
Be extremely wary of buying those cards! They are the equivalent of a "used horses" sale suspiciously located behind a racetrack and smelling of shoe polish.
Any such operation will have run the hardware at its absolute limits, so it will have suffered stress equivalent to years of regular use. It is very possible that even if you can get an original invoice (which is unlikely because most of those cards were diverted before they even hit retail channels), you may be denied warranty for that reason.
Be extremely wary of buying those cards! They are the equivalent of a "used horses" sale suspiciously located behind a racetrack and smelling of shoe polish.
Any such operation will have run the hardware at its absolute limits, so it will have suffered stress equivalent to years of regular use. It is very possible that even if you can get an original invoice (which is unlikely because most of those cards were diverted before they even hit retail channels), you may be denied warranty for that reason.