Multipliers on a 3800+

hey guys, ive been experimenting about with my cpu, messing about with fsb speeds and dividers etc, i have to run a minimum of 240mhz fsb to get my ram back up to 200 mhz (my ram is **** as it is, dont want it to get any worse) with a divider of 5/3. but this means my cpu is running at about 2.9, which i dont really trust on standard cooling, i tried it for a while, but temps got abit scary, so i reduced.

The only way of overclocking the cpu, without having to worry about the ram, would be to change the cpu multiplication, standard its 12x200 to give 2.4, ive oc'd to 220 x 12, which means im running 1100HTT and 220 ram (440),

i went to the menu in my bios to change the cpu multiplier from 12, to say 13+. but the only option i have is 12??

why is this?????

im running a single core 3880+ btw, and a asus a8v mobo

any help will be appreciated

thanks in advance

craaaaaaaaaazy geezer