You should set RAM voltage to the manufacturers specification, regardless of what the BIOS colors it.

With your system at default settings (proc at 3.16ghz, RAM at 800mhz,) you won't be running on a 1:1 ratio. Remember that a 1:1 ratio means that yoru RAM is synced to the base FSBs. Since the base FSB of your proc at stock is 333mhz, RAM needs to be set to 667mhz to run 1:1 (remember that the RAM mhz you set in the BIOS is 2 x base FSB.)

To keep a 1:1 relationship, set RAM manually in the BIOS to 1/2 your FSB. Note that this is really best practice for overclocking. When running at stock, there is no issue having your RAM run at 5:6 ratio (so that it maintains 800mhz.)

For your RAM to run 1:1 at it's stock setting of 800mhz, you will need a 1600mhz FSB. This will give you an overclock of 3.8ghz, considering your chip's multiplier of 9.5