Well it is a hit and miss thing with the volts. I just cranked them up and got 1000 mhz, it depends on your cpu speed. If all you want is 950 then I would start with 1.70v first if it not stable then up it to 1.75v. And program just lets you see what you have, it does not tell you how or how high. It tells you based on the cpu that it will run as high as but I made mine run faster than it said, same with the volt it said 1.75v I hit 1.85v no prob.
Tom's Hardware had some good articles on the duron and athlon cpu's. AMD OverClocking
This is what started me off on the road to o/c my duron and I used an ASUS A7V for years with the duron before my K7S5A.