SOLVED How to Adjust Voltage??

my athlon slot A 705MHZ is supposed to have a
default voltage of 1.60v or 1.65v, but now after
i overclocked it with a GFD (i have plugged off GFD
now), the default voltage is always 1.75v, which i
think is not normal.

how could the GFD make this change? i have
completely plugged it off!

any one know how to adjust the voltage back to
1.60v?? i tried the jumpper on MB, the lowest is
1.60v but when i switched it, it shows 1.70v in BIOS.
and every value that i set by the jumpper on MB
will be +0.10v in actual BIOS, this is so wierd!!!

please help!!!

Don't know about slot A chips, but if I set my core voltage to 1.850v, it shows 1.91v. That could be it.