Overclocking

Athlon II X4 620 comes with upwards locked frequency multiplier, so the only way to overclock it is to raise the HT value. It is good to see that AMD has solved the stability issues that showed up when increasing HT on the first generations of Phenoms. Athlon II X4 620 had no problem whatsoever working on very high 330 MHz HT bus, what resulted an effective speed of 3630 MHz using lowered x11 multiplier. Using higher HT frequency and lower multiplier, same 1333 MHz speeds are achieved for DDR3 memory, the test graphs below are comparable with stock results.

To achieve this clock, core voltage was set to 1.5V. Bumping voltages even more did not result in any significant increase in frequency, but did have a big impact in power consumption. Final clock of 3.63 GHz are nothing spectacular, but again, considering the price of this processor it’s quite satisfying actually. Below you can check the performance differences after overclocking, compared to stock Athlon II X4 620 and stock Phenom II X4 965 working at 3.4 GHz.

Resident Evil 5

Tom Clancy's H.A.W.X.

Cinebench and Handbrake

System Power Consumption