i am wondering if the boards have various revisions of the NB on them and that accounts for better times...my first board was used for the E8500...this 2nd board might be different with a chipset revision...i never checked but something to consider....the first board was down to about 52ns at 520 fsb for the E8500...now, it won't go below 58ns or 62ns at 510 fsb with the 9650 installed.

EDIT...maybe the first NB chipset was higher binned chipset...this one might suck eggs!