FYI, this is a GREAT place to compare Video cards... I just wish they had more to compare in crossfire and SLI.
The GTX 580 is a wonderful card, top of the line. No reason it should break if cooled well. I would keep it no matter what unless you get a fair price somewhere. I don't know how well 6950's in crossfire would work, but the GTX 580 stomps a 1G 6950 any day of the week. Later you could get another 580 and run SLI and stomp harder!
So far as Warrantee, Asus should cover the card anyway if "refurbed" by authorized rep... could email them and ask...
PS: I might add, some companies don't require proof of purchase etc. and go by the serial number to get manufacturing date. When you fill out their online RMA forms, you just click "Online Dealer" for where purchased (like Western Digital does with their hard disks) and get an RMA no problem... so long as the item is within the original allotted warrantee period.
And looks like Asus warrantee is the same way! Don't need proof of purchase!!!Edited by Tex1954 - 5/16/11 at 6:49pm