My 9450 seems to be stonewalled at 3.4, on a 680i w/water.
Runs cool and stable at that, darn near stock volts too, but 427 fsb or so seems as high as it wants to go. More voltage, looser timings, nothing seems to help past that.
It will post, but blue screens after P95 is fired up.
My northbridge is smokin hot as well, almost 30c higher than it ever was on a 6600, or 6750.