How much extra FSB do you get is you increase voltage to SDRAM?

My RAM is maxing out at 149FSB @3.3V. I can up the voltage but want to know what increase in FSB I might see. If you have any idea, please give a worst you've seen and best you've seen.

What kind of RAM do you have?

what are your timings?
2-2-2?
3-3-3?
and dont expect a hole lot more speed out of the RAM by overvolting it. If you cant post at a certain FSB with your RAM set to 3.3V, dont expect it to be stable when overvoltaed at that same FSB.
and as for upping your rams voltage, dont go crazy, 3.8V is pushing it hard, anything higher than that can kill stuff

I have a 256MB of some generic ram, not sure of the brand name, and 128MB of IBM ram. I have tested them seperatly and each stick will get into windows stable at 149FSB. Anything higher then that and when loading windows it reboots/crashes. It will post as speeds up to and over 160FSB, but not get near windows.
Timings are 3-3-3, pretty crap. I think I might go for some Crucial Cas2 stuff, I've seen a few reviews that say this stuff is good to 150 and more. I just want to see if I can squeeze enough out of my current ram before upgrading.
My mobo doesn't really seem to use the cas settings as i have set the ram to cas2 and cas3 on 100FSB, and see only a very small increase in system speed.