it doesn't unlock multipliers of 13 an lower. I'm using an Athlon XP2700+ and having the same issue.
Do you mean the A7N8X?
I'd have to guess that since NF7-S doesn't have the problem that it's possible a future A7N8X BIOS can fix it in that board.
You could mod your chip, close the 5th L3 bridge.
You can also do the wire trick and connect the 8x bit LO, socket pin AJ27 to AH28 (Vss - ground).
<b>99% is great, unless you are talking about system stability</b>