RAM Voltage with CPU OC

I have another computer with Biostar motherboard, and I can't seem to control the RAM timings or the RAM voltage (there is only a RAM overvoltage option) in the BIOS.

Currently, it has a E6300 (stock speed 1.86 GHz), with a minor OC to 2.1 GHz
The DDR2 RAM, which are Kingston 667 2x512mb and 1x1gb sticks increased in voltage from a little under 1.8 to ~1.96

Is this a stable voltage for RAM, or will it burn out prematurely? Thxs