EpIckFa1LJoN :
Unless you can live with the lines, then yes you have to worry if the card is faulty. If you have to downclock I would RMA or get your money back. It's not reaching advertised speeds stable.
But you have to downclock to stock settings to make sure that's what it is.
I have solved the issue... i dug around in the NCP Under video settings i changed the colour settings to use NVidia settings Instead of Video Player settings. And under Image settings i changed the Edge Enhancement to use Nvidia Settings. After that The Fullscreen Mode Worked ..
Thank goodness it was just a small software issue.