The reason I don't think it's the PSU is because I used it in my last build. As for VGA, I haven't fitted it yet, I'm using the onboard GPU temporary. I might give that a try tomorrow morning with the pencil. If I can't pinpoint the problem I will loosen up the screws, it's sitting flat currently in a ghetto spec case. As for the heatsink it's a 6 heat pipe monster but I can't tell you the model right now as I forgot which one I fitted.