Although, I'm ashamed to say, that your post made me LAFF. xD I recently smoked a line on my fan controller which briefly made me panic; I listened to someone else against my better judgement and paid the price, but it could've been worse. lol I managed to get a high-powered server fan running, though! That beast was like a jet engine and is the most powerful fan I have ever
seen; the centripetal force was intense, and the fan would've probably taken my fingers clean off!
Did you by any chance put the 4-pin CPU power cable into the GPU? IDK if that'd even fit, but that could've caused the kaboom. I would assume that you've somehow routed power into the GPU that shouldn't have been there, much like I did with my fan controller. (it still works, though!)
NM, PCI-E cables are 6-pin. >.< My brain's going to mush, again.