I adjust the action with the truss rod back and forth. No matter the action is high or low, I find that theres buzz on the Low E strings only on when:

1. Play open
2. fret at 8th fret
3. Use 80/20 instead of PB

All other notes plays wonderfully! Do you think theres problem with a particular fret? What should I do.

Theres only very slight relief on the neck now (probably less than 1/2 the width of the high E.) and the action on 12th is 4.5/64 High E and 6.5/64 on Low E.

I prefer a action as low as possible, seems like the action can still be lowered by adjusting the saddlle if I can fix the buzz on the Low E.

Any idea? if the buzz only occur when pressing the 8th fret but no problem when pressing the 9th, is there problem with the 9th fret wire on the LOW E?