my AKCA duron900 doesn't o/c very well...i could change the multiplier from the default 9 up to 10.5, but it wouldn't go much higher than that...and it wouldn't stay there long before problems began appearing...i have a FOP32-1 on it, too, and temps never exceeded 51C.
i'd steer clear of durons, if you can, and go with a newer Athlon.