Trying to overclock my system but cannot find memory divider setting in bios?

[simsalabim24]

Yeah so I have been trying to follow this guide:
http://wiki.extremeoverclocking.com/wiki/Athlon_64_Overclocking_Guide

The firs thing it wants you to do is tweak the memory divider setting well I cannot find this setting in my bios anyone point me to it? Thanks!

 

[m1ldslide1]

I used to have an a8n-sli deluxe and the divider setting looked like this:
DDR 400 (changeable to 333, 266, 433, etc)