" i sent it to warranty, they said there is no problem with it, i tried downclocking it, the same thing happens."
I really don't have a clue as to what ELSE would cause this BESIDES the graphics card.
I can't imagine any other software doing it....although try updating to the latest driver if you haven't already.
I can't imagine the CPU doing it, or the MB doing it, or the memory doing it or the HDDs or SSDs doing it...or the PSU doing it.
There's not much left.