Max voltage for PC 3200 ram

What should be the max recommended voltage for my ram? I have 2 sticks of PC 3200 ram that equal 512 MB. My motherboard only gives me these options 2.5, 2.63, 2.77, 2.9. I have never messed with the voltages for my ram or any ram before.

if you overclock high enough 2.9 should be fine dont think it will fry, i run my ram @ 2.8 there hole life time

Thank you