frogtea:
Heck, I would've answered this question the first time I saw it, but I thought it was so silly, that I didn't bother.
Your motherboard has the capability to run the ram completely independant of the FSB, so it will really have nothing to do with your overclock at all.
That is unless you're running linked and synched in your bios.
You're runnning my old mobo, so I do have some experience OCing that board 
E6850@ 3.8 Ghz
GA-P35-DS3R
4Gb-CorsairXMS2-6400 DDR2 800
EVGA 8800 GTS SuperClocked
Tagan TG700 PSU
Seagate Barracuda 400GB SATA 3.0Gb/s
Seagate Barracuda 320GB SATA 3.0Gb/s
Vista Ultimate 64 / XP 64
(2) Samsung SATA Lightscribe DVDRW
Dual Boot OSX & Vista Business RTM / Dell Inspiron 6400