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Some versions of the Phenom II X2 and X3 have one or two cores "deactivated" to enable AMD to target the lower end of its market. As a result, with the correct motherboard and BIOS it is possible to unlock the deactivated core(s) of the processor. However, success is not guaranteed, because in some cases the core(s) may have been deactivated due to faulty silicon. Hardware enthusiast websites have collected and summarized anecdotal reports that, overall, indicate about a 70% success rate but these reports likely have self-reporting bias, and more importantly, it is impossible to know whether an unlocked core is truly bug-free or just works "well enough" for the particular individual making the report.