Yeah, just add 1 more to the FSB only, save to BIOS then cannot boot... Need to remove the casing and touch the cmos jumper....

wat happen if u do 250*10, ram multiplier x2.5?

mine is 250*11(the cpu multiplier is locked, it don't offer me to change), RAM multiplier it only offer me Auto, 1:1.33, 1:1.66. Currently I using 1:1.33 and the RAM frequency is at 667MHz.

i'm afraid u might edi hit the OC limitation for ur board....
if u really looking to get the most of of ur processor, get p35/45 board....

the problem i see here.....
most of the option r locked o not available @ bios.
in order to push clock, u hav 2 push fsb, which result in pushing ram clock also bcoz all these r linked....
ur processor & nb hasn't hit the wall, but ur ram might edi hit the wall, cant go further, causing the oc to fail.

another thing u can try, slap in higher frequency ram, like DDR800....
see if u can push it higher.

I can set the RAM FSB/Ratio to 1:1.33 to get it run at 833MHz, but is it stable?

dat would depends on the oc ability of the ram chip.
IMO, most probably it wont b stable @ 833MHz

try testing wit prime95 or IBT

for your memory.. try use memtest..