Welcome :smile: .
It usually refers to the ratio between to components of your system, usually either the cpu/memory bus speeds(also known as a 'memory divider') or cpu/agp. Some common ratios for example; 4:5, 5:4, 3:2
It is involved with running your cpu and memory at different bus speeds in a ratio that will allow them to be somewhat 'in sync', even though the term is 'asyncronous'.
It is used for overclocking mostly, so you can either raise your FSB for your CPU(overclock) and leave the memory bus speed alone, or the reverse, overclock your memory and leave your CPU fsb at stock speed.
I hope this 'simple explanation' for a complex issue has been of some help. If you have more question, feel free to ask.
A forum community dedicated to tech experts and enthusiasts. Come join the discussion about articles, computer security, Mac, Microsoft, Linux, hardware, networking, gaming, reviews, accessories, and more!