Well from the link i gave u this DDRII mobo does unlock PhenomII X2 555BE with F5 bios.(If the other two cores are not faulty)
Also in the forum itself there are 2-3 ppl who have unlocked the PhenomII X2 555BE with the Gigabyte 785GMT-USB3 (DDRIII one)
Even if it doesnt unlock its a good proccy for gaming due to high clock of 3.2GHz and large L3 cache.
@Aercy:
The reason is that if unlocked the PII X2 555BE --> 955BE (8k). So savings of 3k
Well it depends on the user. If for a user's requirement if a 555BE would suffice then he can go for it and try to unlock. But if the user needs a quad then it is better to go for native quad ones rather than risking it. Here the PII555BE would suffice for the user needs thus the suggestions.