Ram Oc Help

Hi all new to your fourms and Ocing. I been around to a few forms a figured to ask you guys. I run the program cpuz and my ram Freq is set to 1:1 with my FSB. So if i drop my ram freq. to say around 185 then in theory i can boost my FSB up to 215 mhz and my ram is still only going to run at 200mhz, correct me if i am wrong. My question or problem is in my bios there are only 4 settings for ram speeed 400/500/533/auto. I was told i have a good chip, mobo and ram for oc'ing but i cannot seem to get the ram speed down. If anyone is familar with the asus P4P8X SE mobo their help would be very much appreciated.

there's an identical thread like this one, lemme find it.

Thanks

I just read this somewhere in this forum "250MHz FSB speed with 80% or 5:4 (FSB:Memory ratio) results in 200MHz memory speed (DDR400)" Can anyone tell me how to get this 5:4 ratio plz

Anyone ?

its a setting in your BIOS