not necessarily... if you set your memory divider, then when you pump up your cpu FSB, it'll pump up the memory speed too, just not as much as the cpu. try to aim for a configuration where you'll get that highest cpu clock while getting the RAM closest to its rated speed
-your cpu might be a 10x muliplier X 200mhz fsb = 2ghz and with DDR400 RAM, your memory speed is 200mhz.
-when you raise FSB speed, you raise memory speed with it. without a memory divider, you'd be limited to raising everything just no more than 10mhz because value ram doesnt overclock well.
-however, if you set a memory divider, you could set your memory down to, say, 166mhz...which would give you lots of room to raise your FSB while still keeping your RAM under 200mhz.
so you raise your fsb to 250, which puts your ram at 204. which is perfectly okay.
^^^^just an example^^^^ there are many configurations and other specifics to learn about. read any related stickies very thouroughly.
P.S. for AMD processors, FSB = HTT
read this thread i just posted the other day http://www.techist.com/showthread.ph...8&pagenumber=1