The last BIOS was released on 5/10/2006. http://www.foxconnsupport.com/download.aspx?models=&category=C000000001&Series=&keywords=NF4SLI7AA&sort=
So the MB does not support any yorkfield cpu because the yorkfield cpu was released around 2007. http://en.wikipedia.org/wiki/Yorkfield
The last BIOS was released on 5/10/2006. http://www.foxconnsupport.com/download.aspx?models=&category=C000000001&Series=&keywords=NF4SLI7AA&sort=
So the MB does not support any yorkfield cpu because the yorkfield cpu was released around 2007. http://en.wikipedia.org/wiki/Yorkfield