Last week, we spotted an article on a Korean website that showed how to unlock the fourth core on a Phenom II X3 710 processor. Today, the folks at VR-Zone have gleaned some new information about the subject—and they say unlocking isn't just possible on the Korean site's Biostar mobo, but also on boards from DFI, Gigabyte, "and others."
Unlocking purportedly works only with Phenom II X3s from the "0904" batch (meaning chips made on the fourth week of 2009), and just like the Korean site showed, enabling Advanced Clock Calibration in the BIOS should do the trick. As VR-Zone points out, however, the unlockable core may not necessarily be stable. Depending on demand, AMD may prefer to sell parts with four fully functional cores as Phenom II X4s and pocket the extra cash.
VR-Zone's news post also includes a screenshot of an unlocked Phenom II X3 720 Black Edition running on a DFI LanParty 790FX motherboard. The Windows Task Manager detects all four cores with the CPU running at 2.8GHz, which essentially makes it equivalent to a Phenom II X4 920. Well, except the 720 model is over $40 cheaper than its quad-core counterpart.