G.Skill 4266 only boots as 2133, before it was working as DDR3600 with 1800Bus/IF clock since the beginning - opened already another thread for this issue/board.
I even had to start from scratch with my settings, as all of my profiles set lots of values to nonsense (SATA, LAN, Audio, USB3 all to off, VRM switching frequency 15200, ProcOdt to high impedance ...) - all previous Bios version had no issue when loading one of these profiles.