Memory Divider

Hi, I'm new to OCing + have done a lot of research on the subject, however 1thing still escapes my understanding;

What is the benefit of having a 1:1 memory divider? Does it improve performance or just scale back the frequency of the RAM enabling a higher CPU overclock??

Many thanks to all who can help.

A 1:1 divider will help you overclock the CPU without overclocking the RAM too much.