At first, AthlonII X4 620 can overclocks to 3.25GHz in default voltage situation with 650MHz increase of frequency.Next,we continues overclocking with voltage increase. After repeated tests, AthlonII X4 620 can have stable operation at 3.64GHz in 1.496V.
It can be found that AthlonII X4 620 is not better than Athlon II X2 series in overclocking performance.After all it is one quad-core processors,AthlonII X4 620 is more difficult to overclocking.Moreover,increasing FSB to overclock is more critical for motherboard due to lower multiplier.
Performance gets significant improvement after overclocking,especially in games. However,it is noticed that there is no obvious improvement at the range from 3.6GHz to 3.25GHz.So it is suggested that it is OK to overclock in default voltage.
