Sapphire is total crap. 4 cards died on me in the past month alone. One just died completely and three others had cooling fan failures. And no, they were only 73 degrees C hot...
Just a tip, your Power supply is too small...
That wont kill the cards, it'll just kill the PSU.
He probably killed the fans by running them at 100%.
I agree, I've killed cards that way. I do have to say, my HIS IceQx stays at like 30 while mining. I could push nearly 375mh/s if I chose to.