Volcano's are crap.. they kill mobo's because they are so heavy. Yea they are cooler but over time they do there damage.
I'll have to check out your theroy on "its the arctic silver at work" that is cooling it, you may be correct. Ive read good reviews on the coolmaster though, they got a nice one on hardocp that shows its proformance.
maybe you got a bad one? excessive hand oil or something on the heatsink. Or maybe its just crap!
i'll have to put on a different heatsink/fan combo to see if it really its helping.. if not i'll throw the loud bellybutton thing out the window