Your gpu is dying brah.
But if you have a 285 then why would you need to worry about onboard graphics causing problems? Unless the card dies and you need to run through the onboard instead.
But before you go out and buy a new one, you may want to test it on different games and such to see if you can help further level the problem. If it does it across many games, then in all likelyhood it is your GPU.