Almost certainly a BIOS issue. This is something to watch for in particular from high end boards. In my experience the more expensive the motherboard the more likely it is to have a BIOS issue; my reasoning being that shops can usually only afford one, and the one that they buy often stays on the shelf for 3 - 6 months before some 'poor sucker' buys it! By this time a new processor has been released and it's instruction set is slightly different to the one supported by the BIOS that is currently installed on the motherboard! Take it back and have a crack at the shop... If you bought a Gigabyte as for an exchange and try to get your hands on an ASRock. Long story I swore by Gigabyte for many years, but since the GFC (2008) their quality has gone down the drain, and worse never come back!!!