I am going from a dual core to a quad core AMD processor. My MB is the GA-MA790x-ud4p. the Proc is supported but I need to go from the F4 bios to the F7. Do I flash the bios before or after the proc's are swapped?
Always before - when it works with the current processor the bios upgrade will be more stable. And trust me you need bios updates to be as stable as it can.