Was it a catastrophic failure? If not, you might have some luck throwing the 290x in the oven. My 7970 has gained 3 months and counting since it was baked.
There's a thread here on [H] if you wanted to look into it. I can't link it but if you search my username it's my only other post. Title...
Curse you Haste266 (and antipesto93)! I had to break my 8 year lurking streak so I can say thanks for this oven trick.
Baked my reference AMD 7970 this weekend and it went from artifacts during boot/unable to get into Windows back to gaming like normal. I have an electric oven so I preheated it...