My AMD K6 2/350 on the same mobo runs very stable at 400 (4*100 at 2,2V) and 420 (4*105 at 2,4V)though I must say it gets rather hot in the last setting when under heavy load.For example when I play a game like Quake 2 it gets about 60 degr.C but until now my system never crashed.(400 setting about 55C.)Until now I've been using a standard cooler but yesterday I orderd a Cooler Master TI6-602525B which(I hope)will give me better cooling.I think that when I get my temp. down I can even go for the 450(or higher?)So hope this gives you some info and good luck.D.