Recently several reports were published according to which it is possible to unlock the fourth core of AMD's triple-core Athlons. No it seems like it is even possible to transform the Athlon X2 7750 BE into a quad-core CPU.
Athlon X2 7750 with four cores? [Source: view picture gallery]
A screenshot that shows an Athlon X2 7750 BE with four active cores has been published. The older (still 65 nanometers) Kuma core CPU seems to be a quad-core (Barcelona) that had two cores cut off by AMD; possibly because of quality assurance reasons. According to the screenshot
at gigglehd.com GPU-Z recognizes the Athlon X2 7750 BE as an Phenom FX 7750 BE with four cores.
So it seems like the procedure that was successfully tested with newer triple-core Phenoms works in this case, too - it is only necessary to activate ACC in the BIOS. In theory nothing speaks against this procedure, but AMD surly has a reason to deactivate the cores - so there will probably be only a few processors that work correctly with all four cores activated.