oc cpu, ram different clock speeds

[copeyhagen]

hi all,

i have a q6600 G0 @ 2.4 with arctic cooling heatsink and fan, on a asus p5q board, idle temps around 30-35, full load and few hours gaming it maxes at about 55-59 on core 0, rest are slightly lower.

im looking to oc my cpu to 3.0 or 3.2, but i only noticed now my ram has different clock speeds, i have 8 gb ram

2 x 2gb adata ddr pc6400 800 @ 5-5-5-15 and
2 x 2gb crucial ballistix @ 5-5-5-12 or 18 cant remember.

can i overclock my fsb and multiplier to say 9*333 and leave my ram settings as auto?

any guide i have seen has shown to set the ram to manual and eneter clock speeds.

would i be better off running on 4gb crucial ram only?!

thanks

rob