I have the 790gx xe motherboard for my wife. i Put my Be 550 in and using the 1/13/09 bios with acc on auto it will unlock. I think my batch week is the 19. IF you try the newest bios it will not post with acc set to auto. Also that motherboard does not have options to adjust NB. It does work with latest version of AOD to change multiplyer. Voltage changes must be made in bios. This motherboard works ok if you are looking for a mild oc. Say 3.6-3.8 more than that and it doesn't seem to be to stable. I have not tried to raise the base clock so some gains might be had there. But the biggest set back is on not being able to change the NB multipler. I will have a test later this week early next week on the msi 790fx-gd70. I'll let you guys know how it goes.