I had a major problem last Sunday a new graphics card installed in my main computer rig(card was two weeks old), which I also use for gaming packed in, it started smoking. It was not hot and the game I was playing for about 5 mins, I had played for 45mins a few days earlier. I installed a old card I had to test my machine and it worked has normal, what a relief that was I can tell you. The shop I bought it from said bring it in for testing and it smoked on there rig too so they gave me a replacement card.
 I had bought the new card because my Asus Gaming monitor( 9years old) had packed in with the white screen of death a few weeks ago so a new monitor had been aquired with 4k resolution so new graphics card to match. This pc has my old card installed now, I managed to sell one of my older cards to a guy in my Modelshop, so I got some money back from that.
Chris H.

I'm glad to hear that it didn't damage your computer.  It sounds like you were unlucky with the card that you had.

Don't you just hate it when you're dealt duff cards?

A lot of people think of their wedding day like that 

Sounds like you got away lightly - If you follow some of the tech channels on YouTube some of these new cards have issues with power delivery, often melting connectors as they can't take the 400+watts these beasts require when run at their normal potential.  With so much current being drawn any failing component will generate a lot of magic smoke as it gets cooked.

Thanks guys for the comments. A point of interest this new card now has a new connector, they supply a patch lead which allows you to use two feed cables into the patch lead. Looks a bit of a mess, why they have changed from just having two female connectors and using two power cables god knows. I would imagine that new power supplies in the future will have a new socket with equivalent power to two supplies but with just one heavy duty cable that fits this new connector.
Chris H.

I got a replacement card from the retailer, just swapped it. Scan uk very good dealer. New card ok, must have a got a friday afternoon card...lol