A single change on the BIOS of a motherboard can enable the inactive fourth core of the "triple core" AMD Phenom II X3 processors, according to online reports.

A Korean website claims that it has managed to unlock the fourth core of a AMD Phenom II X3 710 processor, which obviously has four cores on the die but the fourth core disabled at the factory.

The website posted photos of the BIOS screen of a Biostar TA790GX 128M motherboard with a Phenom II X3 processor installed.



Setting the "Advanced Clock Calibration" option on the BIOS to "Auto" is enough to unlock the fourth core of the AMD processor and make it show up:





The processor is now recognized as AMD Phenom II X4 10. The web site also run some benchmarks on the "hacked" AMD CPU that showed that the processor is actually performing as a quad core.

It is not clear whether the trick works with any AMD Phenom II X3 processors or with specific series of it. The AMD Phenom II X3 710 is currently listed at $119 at Newegg.com while the cheapest Phenom II X4 (quad-core) CPU running at the same speed (2.6GHz) is listed for $175.99. Intentionally or not, AMD may have given a present to all those who have bought a triple-core X3 CPU.