Bios setting question (AGP)

I am looking for some guidance on what to set the AGP frequency to in the motherboard Bios. Should I raise this from the default 66 mhz? Also, What effect does the agp voltage have on the ability of the card to overclock? I have an XFX 6600gt.

Any feedback would be appreciated.

I leave mine locked at 66 MHz just to keep it stable...
I don't think the 6600GT AGP's benefit from extra voltage since they have the extra molex connector.

Leave it at 66mhz. Anything more or less will make your system unstable at higher overclocks. You won't gain any benifits at all.