Overclocking and Unlocking

Yes, the Athlon X3 425 has one core locked. Yes, it can be unlocked with the proper motherboard, and yes, I did manage do unlock my tested sample to a full Quad Core Athlon II X4.

Trying out the maximum overclock for Athlon II X3 425 pushed the CPU up to 3.51 GHz using 1.500 V core voltage. Bumping the voltages higher did not produce any additional overclock headroom. After finding the max overclock for CPU, HTT and Memory, multipliers were adjusted and the final result was 3.51 GHz core clock, 2080 MHz for HTT and Northbridge and 1390 MHz for system memory.

When trying to unlock the fourth core, additional voltage was needed even on stock settings. To make four cores stable at 2.70 GHz, 1.4525 V core voltage was needed, suggesting the lower quality of the locked core. Surprisingly the processor did manage to achieve the same overclocked frequencies with the unlocked core - but 1.525 V core voltage was needed. Any further voltage bumps did not result in any increase of maximum overclock. Because overclocking had to be done via HT Link, this same clock speed achieved by stock and unlocked cores could suggest a HT Link wall was hit at ~260 MHz.

Overclocked results in a few benchmarks are shown below, as well as power consumption and temperature measurements. Athlon II X3 425 overclocked, with three cores, is shown in green, and overclocked, with four cores, results are shown in blue. Notice the small performance increase in gaming tests, regardless of speed increase or unlocked core.

Resident Evil 5

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

Cinebench and Handbrake

System Power Consumption