Rams have 2 characteristics, one is the DRAM freq, and another is the timing..

an ideal ram will be able to have the highest freq, as well as the tightest timing.. no ram can do that..

so you can only improve either one...

since timing doesn't affect much of the processing speed, its best if you loosen the timing 1st then increase the fsb.. the reason we do this is so that the our oc'ing won't be affected by rams can't cope with high freq and tight timing..

once u got to the max stable fsb you can reach, then you can try tighten timing..