actually, those speeds are not FSB and cpu. they are actually the speed of the RAM and speed of the GPU both on the video card.
But if you mean, do they have to be moved at the same ratio or whatever, I see what you mean and ive wondered this myself. 
With CPU overclocking, the RAM should be in sync with the CPU. So if your cpu fsb is 200, you want memory at 200 too for best performance, not, say, 166 or something.
But I think its different for video cards. I dont think they have the same issue with RAM having to run at a synchronous bus as the GPU, because it seems that sometimes some companies are clocking the cards at totally different speeds.
I, for example, have a Leadtek Nvidia Geforce4 Ti4200. Default speeds are 250/445. I have it now at 320/590. I just pushed both speeds to their limits, separate of each other. If i raise the GPU more, i get white flashes and sparklies and jitters. If i raise memory, I get flashes and jitters. So im guessing that they are pretty much maxed.
make sense?