The point was that the fuse was supposed to blow and stop the card destroying itself.First card looks like the consequences of a poor connection and nothing to do with the card quality. Not sure what happened to the other.
Build quality of Gigabyte parts has always varied widely by market region for some reason, some parts of the world they have a very poor reputation for it, in the UK we seem to get the good stuff mostly. I remember there was a shipment of their Fermi cards intended for the Middle East market that ended up here and they were pretty ropey with rattly and prematurely failing fans, parts like the sheath not sitting flush in place, connectors which had been lazily placed before soldering, etc. etc.