lots of good (but conflicting) feedback! Unfortunately I'm still just as on-the-fence as I was when I started this thread, due to the mixed responses, lol. So let's just say he was actually telling the truth - that this card actually was running at 925Mhz core, under-volted, and kept under 70C in a well-circulated environment. Would that alone cause any degradation to the life-span or overclocking potential of the GPU? If the card is currently working perfectly, do I have much to worry about?
The only reason I'm even considering this particular card is because Gigabyte has a transferrable warranty. However, there isn't much warranty left, because even though it's a 3 year warranty, it's 3 years from the date of manufacture, not the date of sale. I looked at the S/N on the card in the pictures, and it appears it was manufactured in the 18th week of 2011, so there's basically only about a half-year left of manufacture warranty. On top of that, Gigabyte doesn't sell reference 7970s anymore, so they'd end up sending me a crappy refurbished Windforce X3 low-ASIC voltage-locked non-reference 7970, which I have absolutely no interest in. The only protection I get with Gigabyte's warranty is the possibility of selling off the replacement and recouping as much of $325 as possible.
If I buy it, I definitely plan on doing the video of me unboxing it, installing it, and immediately running Unigine and OCCT to check for problems, and I can always file for eBay's buyer protection with that. Yes, $325 is a bit much for a used 7970, but it's getting pretty difficult to find real reference 7970s anymore, and if he's being honest, it's nice knowing I'd be getting a card with a 82.9% ASIC and 1.05v stock voltage that apparently runs cooler than most other reference 7970s. I might try to ask him if his price is negotiable, but he's already sold a couple for that price...
I tend to think he's honest. At least he admitted that it was ran 24/7 for bitcoin mining. Since he has $8000-9000 in graphics cards that he's trying to liquidate, I don't see much reason for him to lie about things like ASIC score and temperature, and when you have that many cards to sell I can understand not wanting to deal with returns and such. I don't know, my other option would be the $410 Sapphire reference 7970 on Newegg right now, but then it's gambling in the silicon lottery again.