Dram Ratio...what is better?

[Eastcoasthandle]

According to this link it indicates that 1:1 is the most desirable Dram Ratio for P4 (I also assume this is true for C2D as well).
So here is my question lets use PC6400/DDR2 800 & either P4-660 or C2D 6700 as an example:
Do you set Dram ratio according to your CPU (1:1)?
Or
Do you set Dram ratio according to your ram (4:5, 3:4, 1:2, etc) depending on what type you get?

I think I got that right...If you increase your ram faster then your FSB there is no noticeable gains when playing games...why?