no, you dont. you can adjust the ram speed, thereby changing the speed at which it runs in relation to the cpu (and the cpu multiplier), but you cant overclock your ram outside those predefined boundaries. ie if you raise your cpu clock, your ram will always raise as well. how much depends on: cpu multiplier, cpu clock speed, and ram speed set in bios.
if you leave it a t 800 you should be able to overclock even the cheapest ram A LITTLE. but if you want your cpu speed high, and dont want to fret over your ram de-stablilizing your overclock, you should set the ram to at least ddr2 667. for high clocks, unless you have some killer ram, you will probably need to set it at ddr2 533. really it depends on what kind of overclock you get on your cpu, and how good at overclocking your ram is.