Have you looked at the Asus support site to see if this is an issue in either their forums or in BIOS updates? Do you have the latest BIOS installed? If there's a MB error, that might clear it up. No offense intended, but it might also be that Sapphire card; my experience with that company is they are prone to hardware errors. It might be worth an RMA, just so you don't have something crop up in the future, after your warranty expires.