Got a new corsair hx650 for my dell xps8300, installed it and everything worked fine for a couple of hours. then i started up a graphics intensive game then about 10mins later my computer just instantly turns off. i tried turning it back on after but it would just "whrr" for a second then turn off again. i put the old psu back in and its fine. so would this be a faulty psu or a connection that wasnt properly connected. i did notice when i was taking the new one out that the cable to the motherboard hadent clipped down, thought it might have been that.