The 'FSB : DRAM' has no pigeonhole or 'global' number - period. There are ratios that do strongly apply on older LGA and AMD, but e.g. 6-core AMD can support DDR3 2000, but some AMD are DDR3 1333 and less; similar with Intel. It all depends upon the 'CPU' and 'OC' vs 'Stock'. The CPU IMC or MOBO MCC dictates the values plus the BIOS settings of Stock vs Rated.