Well, you will find that in the guide, it also mentions to disable those BIOS options, optional as it may be. This is because you want as low a strain on the chipset as possible, and disabling those features means it can "concentrate" easier on the overclocking, rather than running those options + overclocking at the same time.
It is just to reduce the workload of the chipset, in order for a cooler chipset, thus - a more stable overclock.
I don't know why you're having so much trouble finding these things anyway. It can't be that hard, surely...