my first cpu 2200 atlon xp it was 1.65 default in mbm 5.. the new cpu 2600 xp barton 1.70 default why? ihave a7n8x v 2.0 bios 1007

nothing's wrong there.
the def vcore for that cpu is 1.70, that's all

goto bios and just set it to 1,70
and done
maybe the motherboard overvolts the CPU by default to give a little extra stability or its a fault

all well.. all athlon xp must be 1.65 default in bios mine is 1.70 mutch voltage . mutch better heat

ups not 1,70 I meant 1,65
just set it manually !
btw 1,7 and 1,65 don't really make a difference if you come to 1.8 or 1.9 it would make a diff
but those 0.5 will not have much of effekt on heat