According to a recent presentation by MSI, none of the 40+ motherboards (apart from G1.Sniper2) claimed by Gigabyte to support PCI-E 3.0 actually supports it, via hardware.
No actual PCI-E 3.0 devices are currently being sold, so this would've taken a while to be discovered by consumers, and hopefully this will mean dissappointment saved.
Source (Google translate it for you non-Swedes): http://www.sweclockers.com/nyhet/144...pci-express-30