abit be6 overcloking help

[unknown]

i am trying to overclock be6 p-iii 500 to maybe 560, but when i set to mult 5 *
112(1/3), it shows me at 550, instead of 560...do i need to change something
else?
this is my setting:
cpu setting:user defined
turbo: disabled
mult: 5
fsb:112(1/3)
sel#100/66: high
vol core:2.0v (cpu default)

something to change??thanks guys