So I bought a card used for mining on eBay and it's broken. Yeah yeah yeah there were bound to be problems but it's still under warranty so whatever; it was almost half the price of a new one. It's getting RMA'd so I'm safe.
The original owner of the card said he tested all of the batch of cards he was selling and they worked fine. When I got mine and installed it it displayed graphics fine, got high fps in the games I tested. No problems when just in windows(idling at 35C) but in 3d applications after the card went up to 99% usage the temperatures would rise to 80C instantly and crash the card. This happened every time I tested and the last time the card made a high pitched sound like a really fast whirring sound and the screen went gray with vertical lines every few mm. After that the card would not display anything, no POST, no beeps. Power is on though, lights light up, fans spin.
As of now I've put my old card back into my system and everything runs perfectly. I'm just curious as to what on Earth happened.