If the new cpu works, leave the bios setting alone. I only flash it for a new cpu when it won't post. Windows security updates contain most of the driver updates you'll need. Try your favorite games first and see how smooth they run. Use the default settings for awhile (don't overclock the cpu or video card). If you have reboots or video artifacts, first go to a lower resolution setting. If that doesn't work, uninstall your old driver before installing the latest catylist.