Someone on Craigslist is selling an AMD HD6990 for $225. He claims he only used it for MMOs, no bitcoin mining. Normally I would reply "yeah sure" except that the overclock sticker on the card has *NOT* been touched. Would a bitcoin miner actually not overclock this card? Also, could he have overclocked the card with software like Afterburner to avoid touching the switch? I'm a little hesitant about this - I've been looking for a HD 6950 to go tri-Crossifre when I accidently came across this ad, but a few things don't make sense. He claims he's had the card only 10 months yet there is no remaining warranty on it. Deosn't AMD offer 3-year warranty on the HD 6990 as long as you don't hit that overclock switch?