Overclocking and Unlocking the Second Core
Semiconductor Rana core used in the new Athlon II X3 CPUs is fully identical to Propus core. As a result, the new triple-core processors should overclock about the same as Athlon II X4. To check this out we tried overclocking our Athlon II X3 435 CPU in the same testbed as the one we used for performance tests. I would only like to add that we used Thermalright Ultra-120 Extreme processor cooler with Noctua NF-P12 fan to cool the CPU.
Since Athlon II X3 435, just like all other processors from Athlon II family, do not belong to the Black Edition series, they cannot be overclocked by changing the frequency multiplier. To increase their clock frequency over the nominal we need to raise the base clock generator frequency. However, it is no problem: these processors work just fine at a pretty significantly increased base clock. Moreover, since there is no L3 cache, they allow increasing the frequency of the integrated North Bridge part pretty significantly. As a result, the multiplier responsible for this frequency doesn’t need to be lowered during overclocking. The only thing we need to keep an eye on is that the HyperTransport bus frequency stays within acceptable range.
As a result, after we raised the processor Vcore to 1.55 V, we could overclock our Athlon II X3 435 to 3.7 GHz by simply increasing the clock generator frequency to 255 MHz.
The CPU remained totally stable at this frequency and worked without any issues.
The second topic that is of primary interest to many computer enthusiasts after overclocking potential is whether Athlon II X3 processors allow unlocking the fourth core. In reality these CPUs are based on the quad-core die with one locked core. Phenom II X3 processors are built according to the same principle and if you were lucky to a certain extent (namely, if there is no real physical damage to the locked core of the semiconductor die), then you could easily turn them into quad-core ones. Moreover, unlocking the fourth core could be done without any interference on the hardware level by simply enabling Advanced Clock Calibration in the mainboard BIOS Setup. Of course, not every mainboard could do the trick, but, for example, Gigabyte GA-MA790FXT-UD5P definitely could. So, we decided to try and repeat the same “trick” with the Athlon II X 435 processor.
Luckily, we were lucky and the CPU we had successfully transformed into a quad-core one without any issues.
BIOS and diagnostic utilities detected this quad-core processor as Athlon II X3 B35 and it worked perfectly fine under any type of load.
But unfortunately, unlocking the fourth core resulted in a significant lowering of the processor’s overclocking potential. We could only overclock our Athlon II X3 435 with four operational cores to 3.5 GHz.
Obviously, overclocking stalled because of the “defective” fourth core. Nevertheless, the ability to unlock the additional core, even at the expense of some overclocking potential is good news for those users who hope to get more for their money. However, the possibility to unlock the fourth core will not be the feature of all Athlon II X3 CPUs, that’s for sure. We were lucky, but judging by our experience with unlocking Phenom II X3 cores, we can assume that about 50% of all processor can actually allow that.