Thank you for replying!
It's because just my fault that I can't rise voltage.
Now, I can rise voltage to 1.64 V when I do extreme OC.
I'm sorry to have troubled you.
Excuse me, crew.
I often overclock and benchmark my i7 870.
But my machine's OS is Linux, also I use CPU-X in order to get hardware information instead of CPU-Z.
It means I can't submit benchmark score?