Another reason I can not trust ASUS. They are assuming there was no good reason that particular core was turned off in the first place, how misleading for people that won't know better.
http://www.asus.com/News.aspx?N_ID=nUl4pbbLEB9nQu9m
http://www.asus.com/News.aspx?N_ID=nUl4pbbLEB9nQu9m
A Simple Way to Boost Performance with Core Unlocker
Equipped with an exclusive Core Unlocker feature, the M4A89GTD PRO Series allows users to enjoy an instant performance boost by simply turning on a switch on the motherboard. Doing so activates the latent AMD CPU cores and maximizes processing to triple- or quad-core for extreme performance—especially useful for supporting multitasking or intensive processing. By increasing the processing cores, users can also achieve up to 103% better overclocking performance.