overclocking xms2 and 5600

hey guys. just looking for help on overclocking this computer. mobo is an asus m2n-e running a 5600 x2 at 3.0ghz. htt is 1000. bus 250. multi at 12. corsair xms2 pc6400 400mhz running at 500mhz. i've heard that dropping my ram speeds while increasing cpu speed has a greater impact on performance. my idea is to make fsb:ram 1:1. have looked in bios and cant really figure it out. i'm prime stable 24/7 with load temps to 51. idle at 38.
thanks, swim