FX-9590 unstabile at stock clocks

So in deceber I bought a FX-9590 processor because I got a solid deal on it and I just got a cooler for it couple days ago(H115i) so couldn't test it before.. The problem I have is that it isn't stabile at stock speeds. Ran Prime95 and temps were fine but one core stopped working before one minute and second core after two minutes. Does this mean that I have a bad cpu??