I'm not entirely sure. It over volts the FSB, so in effect it would be overvolting everything the FSB is connected to. Personally I use that setting a little as possible as I don't know the answer to that. I would guess that you are hugging the borderline though... It's been my experience that I've not needed it until over a 530FSB when I'm at the board's absolute FSB limit. That said, a quad will certainly stress the FSB heavily, and I've only been playing with a single dualcore so far.