i7 965 with asus R2E question

[PAo_ReVoLT]

hello everybody,

my english is not good so please apologize. so here is the story + question

i try to overclock my i7 965 by raising up cpu ratio. my blck set at 160

so i tried 160 x25 (4.0ghz) when it boot up to window just fine. i checked CPU-Z reading right voltage & cpu ratio so after that i ran prime 95 to see if it stable or not. once CPU hit full load my cpu ratio come down to 24

all temp stay around 50c - 60c

i'm new to this board. anyone that has this combo has the same problem? what fuction in bios i have to turn off?

thank you

ps. latest bios