Well from what i could find by looking around.
It's not bios unleash but just unleash(ing) mode and It's a featured on some Asus Motherboards.
it mean to unlock deactivated cores of Athlon II x3's, Phenom ii x2's, and Phenom II x3's.
although i could be wrong on this,
Chunduru can you give us a better idea what your meaning? Like where you saw this (motherboard bios, ad, a forum).
It would help us out and give you the correct response