Is the bios detecting it as a phenom 560?
The cpu support list doesn't have it, so im guessing the motherboard doesn't know what to do and is just setting it to 800mhz as a safety precaution. (same happens for 125w cpu's that aren't supported)
When you overclock it manually, you should be changing the multiplier and not the bus link. Also make sure to set the VCore to 1.225v (stock voltage) before the frequency change.
Also email biostar and ask them about the support for the 560, they may help by sending you a beta bios which has the updated microcode.
http://206.108.48.60/app/en/support/e-support.php