@penguin1 - I don't think so... my Q6600 B3 can run stock (9x266) @ 1.1ish volts and stay stable to prime95 for 6+ hours. If I bump it up to 9x333 it requires 1.2625V but when I try to push it above that, I have to really up the voltage. In my experience, they don't scale in a linear fashion as you increase FSB with a fixed multiplier. I think they are linear within a certain range, but as you get higher and higher, this isn't true anymore.
...why not set it to whatever you are shooting for and attempt to minimize your vcore testing with p95?