If you purchased an X3 with Propus core (AADAC) that does not have L3 cache, you can probably unlock fourth core and won’t be able to unlock L3 cache. If you are lucky, you have a CPU with AACYC mark, based on Deneb core, which has L3 cache. However, let’s be real: you need a lot of luck to purchase Athlon II X3 for 75€ that can be transformed into 150€ Phenom II. Even if you find CPU with AACYC code, you have slim chances that L3 cache and additional core are operational. It is more likely that you will be able to unlock only fourth core. Frankly, you get more by unlocking core than L3 cache anyway.

The same can be sad for Athlon II X4 with AADAC mark, because you won’t be able to unlock L3 cache, because there is none. In case you stumble upon CPU with AACYC mark, you have good chances in transforming it to Phenom II X4. Athlon II with AACYC mark also has slightly higher overclock potentials.

Overclocking and Unlocking

Propus core is not that good overclocking material as Deneb is, just as it was the case with Athlon 64 S939, where Venice core with 512MB L2 was slightly worse overclocker than San Diego core with 1MB L2 cache. We managed to reach stable 3.6GHz under 1.45V for cores with our Propus CPU. Integrated northbridge operated at 2660MHz under 1.4V, which was more than Athlon II X3 needed at same frequency. Nevertheless, at same frequency Athlon II X4 finished all stress tests. Propus stubbornly refused to boot up at frequencies higher than 3700MHz. Results achieved at 3.6GHz are comparable to Phenom II 955 and 965 CPUs.
On the other hand, to unlock Athlon II X3 we needed luck and knowledge. Beside these, you also need a good motherboard capable to do such job. Motherboard should have SB750 or SB710 and ACC (Advanced Clock Calibration). On Gigabyte motherboards, you should set EC Firmware at Hybrid and ACC for all cores at Auto.

On most SB750 and SB710 motherboards, only ACC should be enabled. After that, system should boot up and new Phenom II X4 B35 CPU should be recognized. If you have Athlon II X4 620 and you can unlock its L3 cache you will end up with Phenom II X4 B20. If automatic settings for ACC won’t do, you should try with manual settings and manual clock signal calibration. This depends on exact sample of CPU. Our sample unlocked its potentials at ACC +2% and +4%. This wasn’t enough for absolute stable operational conditions. We also needed to raise voltage on northbridge and L3 cache, after which situation stabilized.  Some samples will work just with ACC Auto settings.