The early revisions of the nForce2 chipsets shared one common flaw - the north bridge chip's surface wasn't flat. Because of that flaw, the north bridge's heat sink cannot actually make full contact with the north bridge. The situation improved a lot with the introduction of the nForce2 Ultra 400 chipset but unfortunately, they still couldn't make them completely flat. An imperfect contact surface is one of the best excuses to wet-sand your north bridge and that's exactly what I did. Believe it or not, the result was fantastic! Come and check out how I did it! Link : The North Bridge Wet-Sanding Guide!