Name & shame I say. I have had similar problems with 3 top-of-range Asus mobo's in the last year! At £270 per mobo it's obvious this manu has lost their excellent quality control reputation just like Abit did a year or two before they left the business. It wasn't just early adopters blues some of these prob's happened well into the kits life cycle!
I currently use another (AsRock) manu's (2 x PC builds for personal use) mobo's at a quarter of the price, which hasnít let me down yet over the same period as the Asus. And if these cheaper mobo's go belly-up & the retailer says I've voided my warranty at least it's not so expensive a loss. I sacrifice some features like twin pairing of gigabit ports & 790sli but gained some other features like Intel x48 rock solid chipset & DDR2 / DDR3 compatibility flexibility at a fraction of the cost.
It's a shame as I use to trust Asus gear but 7 months of trying to prove to their China tech support it wasn't my fault their mobo's were faulty / not compatible left me jaded. Only by naming / shaming & voting with my feet / cash elsewhere can we get them to act!
It's good to share, right? That feels better.