1.7 is low...
I've seen people pumping all the way to 2.0v for Bartons, but it is not very highly advisable to do that for the long run.

Wat are the specs of your rams?
If possible, try tweaking all the setttings yourself rather than relying on the mobo to overclock your rams.
If you're running DDR400 rams, u might wanna set ur rams to run at 166 and start from there, running 1:1 is always more result yielding than any ratios.
Btw, what cooler are you running? Try to get something like an Si-97 at least. You should see an idle temperature in the high 30s or low 40s and a load temp below 50.
Try to pump in extra voltage and move up gradually, if you're not very confident in the voltage thingy, try to limit it within 1.75 and see whats the max you can get from it. Abit boards have a tendency to overvolt...