What were you mining with them? If you bought new, I am assuming it was late 2013 and you were mining Scrypt which was litecoin.
From what I recall, the R9 290 was a complete power-hog with Scrypt and if you ran with stock voltage they pulled 350-400Watts per GPU easily and due to poor heat control, they easily burnt up.
Not sure what coins I was mining back then, probably scrypt (vtc and doges mostly, iirc) and other algos that made sense at that time, but never mined with stock voltage on any gpu and definitely not 290s - always undervolting. Maybe just got unlucky.