It should be ... http://www.asrock.com/mb/overview.asp?Model=Z68 Extreme3 Gen3
because it say
To run the PCI Express 3.0 slots in Gen 3 speed, please must install the Ivy Bridge CPU which supports PCI Express 3.0. If you install the Sandy Bridge CPU, the PCI Express 3.0 slots will run only at Gen2 speed."
so will assume it support IvyBridge CPU .... otherwise this is meaningless.....