found it under asus global - I guess asus usa don't want you to know these things ??
http://www.asus.com/Motherboards/M5A78LM_LX/HelpDesk_CPU/
you will need bios 1401 to support that chip
FX-8300(FD8300WMW8KHK,3.2GHz,8C,95W,rev.C0,AM3+) ALL ''1401 ''